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
By using the synmeby and the qusi-symmetry of the infinitesimal transformation of the transformation group G1 and by imposing restrictions of constraints on the transformation, the Noether's theory of constrained ...By using the synmeby and the qusi-symmetry of the infinitesimal transformation of the transformation group G1 and by imposing restrictions of constraints on the transformation, the Noether's theory of constrained Birkhoffian system has been established. The theory includes the generalized Noether's theorem obtaining the first integrals from the known symmetry and quasi-symmetry and its inverse obtaining the corresponding symmetry and quasi-symmetry from the known first integrals for the systerm.展开更多
In this paper, we present a new method to construct the conservation laws for relativistic mechanical systems by finding corresponding integrating factors. First, the Lagrange equations of relativistic mechanical syst...In this paper, we present a new method to construct the conservation laws for relativistic mechanical systems by finding corresponding integrating factors. First, the Lagrange equations of relativistic mechanical systems are established, and the definition of integrating factors of the systems is given; second, the necessary conditions for the existence of conserved quantities of the relativistic mechanical systems are studied in detail, and the relation between the conservation laws and the integrating factors of the systems is obtained and the generalized Killing equations for the determination of the integrating factors are given; finally, the conservation theorem and its inverse for the systems are established, and an example is given to illustrate the application of the results.展开更多
AIM:To study and provide data on the evolution of medical procedures and outcomes of patients suffering from perforated midgut diverticulitis. METHODS:Three data sources were used:the Medline and Google search engines...AIM:To study and provide data on the evolution of medical procedures and outcomes of patients suffering from perforated midgut diverticulitis. METHODS:Three data sources were used:the Medline and Google search engines were searched for case reports on one or more patients treated for perforated midgut diverticulitis (Meckel's diverticulitis excluded) that were published after 1995. The inclusion criterion was sufficient individual patient data in the article. Both indexed and non-indexed journals were used. Patients treated for perforated midgut diverticulitis at Vestfold Hospital were included in this group. Data on symptoms, laboratory and radiology results, treatment modalities, surgical access, procedures, complications and outcomes were collected. The Norwegian patient registry was searched to find patients operated upon for midgut diverticulitis from 1999 to 2007. The data collected were age, sex, mode of access, surgical procedure performed and number of patients per year. Historical controls were retrieved from an article published in 1995 containing pertinent individual patient data. Statistical analysis was done with SPSS software.RESULTS:GroupⅠ:106 patients (48 men) were found. Mean age was 72.2 ± 13.1 years (mean ± SD). Age or sex had no impact on outcomes (P = 0.057 and P = 0.771, respectively). Preoperative assessment was plain radiography in 53.3% or computed tomography (CT) in 76.1%. Correct diagnosis was made in 77.1% with CT, 5.6% without (P = 0.001). Duration of symptoms before hospitalization was 3.6 d (range:1-35 d), but longer duration was not associated with poor outcome (P = 0.748). Eighty-six point eight percent of patients underwent surgery, 92.4% of these through open access where 90.1% had bowel resection. Complications occurred in 19.2% of patients and 16.3% underwent reoperation. Distance from perforation to Treitz ligament was 41.7 ± 28.1 cm. At surgery, no peritonitis was found in 29.7% of patients, local peritonitis in 47.5%, and diffuse peritonitis in 22.8%. Peritonitis grade correlated with the reoperation rate (r = 0.43). Conservatively treated patients had similar hospital length of stay as operated patients (10.6 ± 8.3 d vs 10.7 ± 7.9 d, respectively). Age correlated with hospital stay (r = 0.46). No difference in outcomes for operated or nonoperated patients was found (P = 0.814). Group Ⅱ:113 patients (57 men). Mean age 67.6 ± 16.4 years (range: 21-96 years). Mean age for men was 61.3 ± 16.2 years, and 74.7 ± 12.5 years for women (P = 0.001). Number of procedures per year was 11.2 ± 0.9, and bowel resection was performed in 82.3% of patients. Group Ⅲ: 47 patients (21 men). Patient age was 65.4 ± 14.4 years. Mean age for men was 61.5 ± 17.3 years and 65.3 ± 14.4 years for women. Duration of symptoms before hospitalization was 6.9 d (range: 1-180 d). No patients had a preoperative diagnosis, 97.9% of patients underwent surgery, and 78.3% had multiple diverticula. Bowel resection was performed in 67.4% of patients, and suture closure in 32.6%. Mortality was 23.4%. There was no difference in length of history or its impact on survival between Groups Ⅰ and Ⅲ (P = 0.241 and P = 0.198, respectively). Resection was more often performed in Group Ⅰ (P = 0.01). Mortality was higher in Group Ⅲ (P = 0.002). CONCLUSION: In cases with contained perforation, conservative treatment gives satisfactory results, laparosco-py with lavage and drainage can be attempted and continued with a conservative course.展开更多
The integrating factors and conservation theorems of nonholonomic dynamical system of relative motion are studied. First, the dynamical equations of relative motion of system are written. Next, the definition of integ...The integrating factors and conservation theorems of nonholonomic dynamical system of relative motion are studied. First, the dynamical equations of relative motion of system are written. Next, the definition of integrating factors is given, and the necessary conditions for the existence of the conserved quantities are studied in detail. Then, the conservation theorem and its inverse of system are established. Finally, an example is given to illustrate the application of the result.展开更多
For a Birkhoffing system in the event space, a general approach to the construction of conservation laws is presented. The conservation laws are constructed by finding corresponding integrating factors for the paramet...For a Birkhoffing system in the event space, a general approach to the construction of conservation laws is presented. The conservation laws are constructed by finding corresponding integrating factors for the parametric equations of the system. First, the parametric equations of the Birkhoffian system in the event space are established, and the definition of integrating factors for the system is given; second the necessary conditions for the existence of conservation laws are studied in detail, and the relation between the conservation laws and the integrating factors of the system is obtained and the generalized Killing equations for the determination of the integrating factors are given; finally, the conservation theorem and its inverse for the system are established, and an example is given to illustrate the application of the results.展开更多
The conservation theorems of the generalized Lagrangian equations for nonconservative mechanical system are studied by using method of integrating factors. Firstly, the differential equations of motion of system are g...The conservation theorems of the generalized Lagrangian equations for nonconservative mechanical system are studied by using method of integrating factors. Firstly, the differential equations of motion of system are given, and the definition of integrating factors is given. Next, the necessary conditions for the existence of the conserved quantity are studied in detail. Finally, the conservation theorem and its inverse for the system are established, and an example is given to illustrate the application of the result.展开更多
The relation between the toal variation of classical field theory and the multisymplectic structure is shown. Then the multisymplectic structure and the corresponding multisymplectic conservation of the coupled nonlin...The relation between the toal variation of classical field theory and the multisymplectic structure is shown. Then the multisymplectic structure and the corresponding multisymplectic conservation of the coupled nonlinear Schroedinger system are obtained directly from the variational principle.展开更多
Self-adjoint theorem is introduced to match the corresponding functional of the given differential equations,and then Noether＇s theorem is used to determine the extended conservation laws of the original equations. F...Self-adjoint theorem is introduced to match the corresponding functional of the given differential equations,and then Noether＇s theorem is used to determine the extended conservation laws of the original equations. Finally, as the application of the method, the conservation laws of Drinfel＇d-Sokolov-Wilson equation and Benjamin-Bona-Mahony equation are constructed.展开更多
Conservation laws of some differential equations in fiance are studied in this paper. This method does not involve the use or existence of a variational principle. As an alternative, linearize the given equation and f...Conservation laws of some differential equations in fiance are studied in this paper. This method does not involve the use or existence of a variational principle. As an alternative, linearize the given equation and find adjoint equation of the linearized equation, the conservation laws can be constructed directly from the symmetries and adjoint symmetries of the associated linearized equation and its adjoint equation.展开更多
In this paper, we study Lie symmetry and conserved quantities for a mechanical-electrical system. The criterion of the Lie symmetry for this system is given. The generalized Hojman conserved quantity and generalized L...In this paper, we study Lie symmetry and conserved quantities for a mechanical-electrical system. The criterion of the Lie symmetry for this system is given. The generalized Hojman conserved quantity and generalized Lutzky conserved quantity deduced from the Lie symmetry for the system are obtained. An example is presented to illustrate the results.展开更多
Based on the sample data of the listed firms on the A stock market, we analyze how the system of independent directors influence the earning conservatism from 4 dimensions designed to measure the monitoring power of t...Based on the sample data of the listed firms on the A stock market, we analyze how the system of independent directors influence the earning conservatism from 4 dimensions designed to measure the monitoring power of these independent directors： Percentage within BDs, professional capacities, stimulation and work conditions. From the empirical results, we conclude that the more powerful of the independent directors, the better the accounting conservatism, and that their positive impact increases along with the improvement on corporate governance, meanwhile the work conditions plays the most important role, and then are the percentage within BDs and their professional capacities, the stimulation and personal reputation appear the least importance.展开更多
文摘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.
文摘By using the synmeby and the qusi-symmetry of the infinitesimal transformation of the transformation group G1 and by imposing restrictions of constraints on the transformation, the Noether's theory of constrained Birkhoffian system has been established. The theory includes the generalized Noether's theorem obtaining the first integrals from the known symmetry and quasi-symmetry and its inverse obtaining the corresponding symmetry and quasi-symmetry from the known first integrals for the systerm.
基金Natural Science Foundation of High Education of Jiangsu Province of China，"Qing Lan" Project Foundation of Jiangsu Province
文摘In this paper, we present a new method to construct the conservation laws for relativistic mechanical systems by finding corresponding integrating factors. First, the Lagrange equations of relativistic mechanical systems are established, and the definition of integrating factors of the systems is given; second, the necessary conditions for the existence of conserved quantities of the relativistic mechanical systems are studied in detail, and the relation between the conservation laws and the integrating factors of the systems is obtained and the generalized Killing equations for the determination of the integrating factors are given; finally, the conservation theorem and its inverse for the systems are established, and an example is given to illustrate the application of the results.
文摘AIM:To study and provide data on the evolution of medical procedures and outcomes of patients suffering from perforated midgut diverticulitis. METHODS:Three data sources were used:the Medline and Google search engines were searched for case reports on one or more patients treated for perforated midgut diverticulitis (Meckel's diverticulitis excluded) that were published after 1995. The inclusion criterion was sufficient individual patient data in the article. Both indexed and non-indexed journals were used. Patients treated for perforated midgut diverticulitis at Vestfold Hospital were included in this group. Data on symptoms, laboratory and radiology results, treatment modalities, surgical access, procedures, complications and outcomes were collected. The Norwegian patient registry was searched to find patients operated upon for midgut diverticulitis from 1999 to 2007. The data collected were age, sex, mode of access, surgical procedure performed and number of patients per year. Historical controls were retrieved from an article published in 1995 containing pertinent individual patient data. Statistical analysis was done with SPSS software.RESULTS:GroupⅠ:106 patients (48 men) were found. Mean age was 72.2 ± 13.1 years (mean ± SD). Age or sex had no impact on outcomes (P = 0.057 and P = 0.771, respectively). Preoperative assessment was plain radiography in 53.3% or computed tomography (CT) in 76.1%. Correct diagnosis was made in 77.1% with CT, 5.6% without (P = 0.001). Duration of symptoms before hospitalization was 3.6 d (range:1-35 d), but longer duration was not associated with poor outcome (P = 0.748). Eighty-six point eight percent of patients underwent surgery, 92.4% of these through open access where 90.1% had bowel resection. Complications occurred in 19.2% of patients and 16.3% underwent reoperation. Distance from perforation to Treitz ligament was 41.7 ± 28.1 cm. At surgery, no peritonitis was found in 29.7% of patients, local peritonitis in 47.5%, and diffuse peritonitis in 22.8%. Peritonitis grade correlated with the reoperation rate (r = 0.43). Conservatively treated patients had similar hospital length of stay as operated patients (10.6 ± 8.3 d vs 10.7 ± 7.9 d, respectively). Age correlated with hospital stay (r = 0.46). No difference in outcomes for operated or nonoperated patients was found (P = 0.814). Group Ⅱ:113 patients (57 men). Mean age 67.6 ± 16.4 years (range: 21-96 years). Mean age for men was 61.3 ± 16.2 years, and 74.7 ± 12.5 years for women (P = 0.001). Number of procedures per year was 11.2 ± 0.9, and bowel resection was performed in 82.3% of patients. Group Ⅲ: 47 patients (21 men). Patient age was 65.4 ± 14.4 years. Mean age for men was 61.5 ± 17.3 years and 65.3 ± 14.4 years for women. Duration of symptoms before hospitalization was 6.9 d (range: 1-180 d). No patients had a preoperative diagnosis, 97.9% of patients underwent surgery, and 78.3% had multiple diverticula. Bowel resection was performed in 67.4% of patients, and suture closure in 32.6%. Mortality was 23.4%. There was no difference in length of history or its impact on survival between Groups Ⅰ and Ⅲ (P = 0.241 and P = 0.198, respectively). Resection was more often performed in Group Ⅰ (P = 0.01). Mortality was higher in Group Ⅲ (P = 0.002). CONCLUSION: In cases with contained perforation, conservative treatment gives satisfactory results, laparosco-py with lavage and drainage can be attempted and continued with a conservative course.
基金The project supported by Natural Science Foundation of Heilongjiang Province of China under Grant No. 9507
文摘The integrating factors and conservation theorems of nonholonomic dynamical system of relative motion are studied. First, the dynamical equations of relative motion of system are written. Next, the definition of integrating factors is given, and the necessary conditions for the existence of the conserved quantities are studied in detail. Then, the conservation theorem and its inverse of system are established. Finally, an example is given to illustrate the application of the result.
基金the Natural Science Foundation of Higher Education Institution of Jiangsu Province of China under Grant Nos.04KJA130135 and 08KJB13002
文摘For a Birkhoffing system in the event space, a general approach to the construction of conservation laws is presented. The conservation laws are constructed by finding corresponding integrating factors for the parametric equations of the system. First, the parametric equations of the Birkhoffian system in the event space are established, and the definition of integrating factors for the system is given; second the necessary conditions for the existence of conservation laws are studied in detail, and the relation between the conservation laws and the integrating factors of the system is obtained and the generalized Killing equations for the determination of the integrating factors are given; finally, the conservation theorem and its inverse for the system are established, and an example is given to illustrate the application of the results.
基金The project supported by the Natural Science Foundation of Heilongjiang Province of China under Grant No. 9507
文摘The conservation theorems of the generalized Lagrangian equations for nonconservative mechanical system are studied by using method of integrating factors. Firstly, the differential equations of motion of system are given, and the definition of integrating factors is given. Next, the necessary conditions for the existence of the conserved quantity are studied in detail. Finally, the conservation theorem and its inverse for the system are established, and an example is given to illustrate the application of the result.
基金The project supported by National Natural Science Foundation of China under Grant Nos. 10401033 and 10471145 and the Key Project of Knowledge Innovation of CAS under Grant No. KZCX1-SW-18
文摘The relation between the toal variation of classical field theory and the multisymplectic structure is shown. Then the multisymplectic structure and the corresponding multisymplectic conservation of the coupled nonlinear Schroedinger system are obtained directly from the variational principle.
基金Supported by "Math + X" Fund of Dalian University of Technology, Science Foundation of Dalian University of Technology under Grant No. SFDUT0808the National Key Basic Research Development of China under Grant No. 2004CB318000
文摘Self-adjoint theorem is introduced to match the corresponding functional of the given differential equations,and then Noether＇s theorem is used to determine the extended conservation laws of the original equations. Finally, as the application of the method, the conservation laws of Drinfel＇d-Sokolov-Wilson equation and Benjamin-Bona-Mahony equation are constructed.
基金the National Natural Science Foundation of China under
文摘Conservation laws of some differential equations in fiance are studied in this paper. This method does not involve the use or existence of a variational principle. As an alternative, linearize the given equation and find adjoint equation of the linearized equation, the conservation laws can be constructed directly from the symmetries and adjoint symmetries of the associated linearized equation and its adjoint equation.
文摘In this paper, we study Lie symmetry and conserved quantities for a mechanical-electrical system. The criterion of the Lie symmetry for this system is given. The generalized Hojman conserved quantity and generalized Lutzky conserved quantity deduced from the Lie symmetry for the system are obtained. An example is presented to illustrate the results.
文摘Based on the sample data of the listed firms on the A stock market, we analyze how the system of independent directors influence the earning conservatism from 4 dimensions designed to measure the monitoring power of these independent directors： Percentage within BDs, professional capacities, stimulation and work conditions. From the empirical results, we conclude that the more powerful of the independent directors, the better the accounting conservatism, and that their positive impact increases along with the improvement on corporate governance, meanwhile the work conditions plays the most important role, and then are the percentage within BDs and their professional capacities, the stimulation and personal reputation appear the least importance.
