Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in ...Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in gas hydrate. The relationships of hydrate rate, capacity and liquid temperature versus time were derived and three results were contrasted. The experimental results show lowtemperature and constant-pressure method is better than the other two methods because it's operation period is shorter and storage capacity is larger than the other two. Low-temperature and constant-pressure method is the best method. So new method will be new research objective.展开更多
AIM: To establish a scoring system for predicting the incidence of postoperative complications and mortality in general surgery based on the physiological and operative severity score for the enumeration of mortality ...AIM: To establish a scoring system for predicting the incidence of postoperative complications and mortality in general surgery based on the physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM), and to evaluate its efficacy. METHODS: Eighty-four patients with postoperative complications or death and 172 patients without postoperative complications, who underwent surgery in our department during the previous 2 years, were retrospectively analyzed by logistic regression. Fifteen indexes were investigated including age, cardiovascular function, respiratory function, blood test results, endocrine function, central nervous system function, hepatic function, renal function, nutritional status, extent of operative trauma, and course of anesthesia. Modified POSSUM (M-POSSUM) was developed using significant risk factors with its efficacy evaluated. RESULTS: The significant risk factors were found to be age, cardiovascular function, respiratory function, hepatic function, renal function, blood test results, endocrine function, nutritional status, duration of operation, intraoperative blood loss, and course of anesthesia. These factors were all included in the scoring system. There were significant differences in the scores between the patients with and without postoperative complications, between the patients died and survived with complications, and between the patients died and survived without complications. The receiver operating characteristic curves showed that the M-POSSUM could accurately predict postoperative complications and mortality.CONCLUSION: M-POSSUM correlates well with postoperative complications and mortality, and is more accurate than POSSUM.展开更多
Introduction: Perioperative hypothermia in cardiac surgery is associated with adverse outcome. The aim of this investigation was to study whether an underbody forced-air warming blanket during coronary artery bypass g...Introduction: Perioperative hypothermia in cardiac surgery is associated with adverse outcome. The aim of this investigation was to study whether an underbody forced-air warming blanket during coronary artery bypass graft surgery with normothermic cardiopulmonary bypass can prevent postoperative hypothermia. Methods: After Medical Ethics Committee approval, 60 low-risk cardiac surgery patients at random were assigned into a group that received standard thermal care management (control group n = 30) and a group that received the underbody forced-air warming system plus the standard thermal care (intervention group n = 30). Results: The temperature after-drop from the end of cardiopulmonary bypass to arrival in the ICU was less in the intervention group versus control group (0.4°C ± 0.3°C vs 0.6°C ± 0.4°C;P = 0.027). Out of the intervention group, 27 patients arrived in the ICU with a bladder temperature ? 36°C (90%) as compared to 14 patients (46.7%) from the control group (P < 0.001). The peripheral temperature was significantly higher in the intervention group as compared to the control group (P < 0.001). Conclusions: A full underbody forced-air warming blanket prevents postoperative hypothermia in normothermic coronary artery bypass graft surgery patients.展开更多
In this paper, a modified Newton type iterative method is considered for ap- proximately solving ill-posed nonlinear operator equations involving m-accretive mappings in Banach space. Convergence rate of the method is...In this paper, a modified Newton type iterative method is considered for ap- proximately solving ill-posed nonlinear operator equations involving m-accretive mappings in Banach space. Convergence rate of the method is obtained based on an a priori choice of the regularization parameter. Our analysis is not based on the sequential continuity of the normalized duality mapping.展开更多
The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and therm...The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines.展开更多
The convergence of several Galerkin-Petrov methods, including polynomial collocation and analytic element collocation methods of Toeplitz operators on Dirichlet space, is established. In particular, it is shown that s...The convergence of several Galerkin-Petrov methods, including polynomial collocation and analytic element collocation methods of Toeplitz operators on Dirichlet space, is established. In particular, it is shown that such methods converge if the basis and test function own certain circular symmetry.展开更多
In this paper we develop two multilevel iteration methods for solving linear systems resulting from the Galerkin method and Tikhonov regularization for linear ill-posed problems. The two algorithms and their convergen...In this paper we develop two multilevel iteration methods for solving linear systems resulting from the Galerkin method and Tikhonov regularization for linear ill-posed problems. The two algorithms and their convergence analyses are presented in an abstract framework.展开更多
Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the id...Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery.Methods:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed.The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries.Finally,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time groups.Results:The statistically calculated ideal operative time was 135.4-165.4 min.The longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 min.Regardless of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies annually.Conclusions:Operative time longer than the ideal time range(especially≥240 min)should be avoided.If the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better prognosis.Efforts to minimize operative time should be attempted with sufficient surgical experience.展开更多
BACKGROUND As one of the major abdominal operations,pancreaticoduodenectomy(PD)involves many organs.The operation is complex,and the scope of the operation is large,which can cause significant trauma in patients.The o...BACKGROUND As one of the major abdominal operations,pancreaticoduodenectomy(PD)involves many organs.The operation is complex,and the scope of the operation is large,which can cause significant trauma in patients.The operation has a high rate of complications.Pancreatic leakage is the main complication after PD.When pancreatic leakage occurs after PD,it can often lead to abdominal bleeding and infection,threatening the lives of patients.One study found that pancreatic leakage was affected by many factors including the choice of pancreaticojejunostomy method which can be well controlled.AIM To investigate the choice of operative methods for pancreaticojejunostomy and to conduct a multivariate study of pancreatic leakage in PD.METHODS A total of 420 patients undergoing PD in our hospital from January 2014 to March 2019 were enrolled and divided into group A(n=198)and group B(n=222)according to the pancreatointestinal anastomosis method adopted during the operation.Duct-to-mucosa pancreatojejunostomy was performed in group A and bundled pancreaticojejunostomy was performed in group B.The operation time,intraoperative blood loss,and pancreatic leakage of the two groups were assessed.The occurrence of pancreatic leakage after the operation in different patients was analyzed.RESULTS The differences in operative time and intraoperative bleeding between groups A and B were not significant(P>0.05).In group A,the time of pancreatojejunostomy was 26.03±4.40 min and pancreatic duct diameter was 3.90±1.10 mm.These measurements were significantly higher than those in group B(P<0.05).The differences in the occurrence of pancreatic leakage,abdominal infection,abdominal hemorrhage and gastric retention between group A and group B were not significant(P>0.05).The rates of pancreatic leakage in patients with preoperative albumin<30 g/L,preoperative jaundice time≥8 wk,and pancreatic duct diameter<3 mm,were 23.33%,33.96%,and 19.01%,respectively.These were significantly higher than those in patients with preoperative albumin≥30 g/L,preoperative jaundice time<8 wk,and pancreatic duct diameter≥3 cm(P<0.05).Logistic regression analysis showed that preoperative albumin<30 g/L,preoperative jaundice time≥8 wk,and pancreatic duct diameter<3 mm were risk factors for pancreatic leakage after PD(odds ratio=2.038,2.416 and 2.670,P<0.05).CONCLUSION The pancreatointestinal anastomosis method during PD has no significant effect on the occurrence of pancreatic leakage.The main risk factors for pancreatic leakage include preoperative albumin,preoperative jaundice time,and pancreatic duct diameter.展开更多
After discretization by the finite volume method,the numerical solution of fractional diffusion equations leads to a linear system with the Toeplitz-like structure.The theoretical analysis gives sufficient conditions ...After discretization by the finite volume method,the numerical solution of fractional diffusion equations leads to a linear system with the Toeplitz-like structure.The theoretical analysis gives sufficient conditions to guarantee the positive-definite property of the discretized matrix.Moreover,we develop a class of positive-definite operator splitting iteration methods for the numerical solution of fractional diffusion equations,which is unconditionally convergent for any positive constant.Meanwhile,the iteration methods introduce a new preconditioner for Krylov subspace methods.Numerical experiments verify the convergence of the positive-definite operator splitting iteration methods and show the efficiency of the proposed preconditioner,compared with the existing approaches.展开更多
Objective:To explore the application effectiveness of the“Six-Step”Scenario-Based Teaching Method in operating room nursing education.Methods:Seventy nursing students undergoing clinical training in the operating ro...Objective:To explore the application effectiveness of the“Six-Step”Scenario-Based Teaching Method in operating room nursing education.Methods:Seventy nursing students undergoing clinical training in the operating room of a certain hospital from January 2024 to June 2025 were selected.They were randomly divided into an observation group(n=35)and a control group(n=35)using a random number table.The control group received traditional“mentor-apprentice”on-the-job training,while the observation group underwent the“six-step”scenario-based teaching method.The two groups were compared on final assessment scores,comprehensive competency,surgical nursing emergency response ability,and teaching satisfaction indicators.Results:The observation group achieved significantly higher final assessment scores(85.54±5.05)than the control group(78.63±4.75);After instruction,the observation group scored significantly higher than the control group in:mastery of basic duties and procedures(4.22±0.30 vs.3.98±0.30),understanding of surgical nursing essentials(4.39±0.19 vs.3.98±0.30),proficiency in surgical assistance(4.11±0.33 vs.3.98±0.30),aseptic awareness(4.32±0.24 vs.3.98±0.30),risk awareness(4.22±0.17 vs.3.98±0.30),and occupational safety awareness(4.01±0.23 vs.3.98±0.30).(4.01±0.23),which were significantly higher than the control group’s scores(3.36±0.28),(3.14±0.27),(3.29±0.24),(3.53±0.36),(3.17±0.25),and(3.51±0.18),respectively.Students in the observation group scored significantly higher than the control group in emergency hands-on skills(24.53±1.85 points),surgical coordination skills(27.65±1.87 points),emergency coordination skills(25.34±1.83 points),and patient condition observation skills(24.34±1.79 points)were significantly higher than those of the control group(20.78±1.74 points,26.31±1.95 points,22.92±1.69 points,and 21.58±1.77 points,respectively).The satisfaction rate with operating room nursing education among students in the observation group(97.00%)was significantly higher than that in the control group(77.00%).All differences were statistically significant(p<0.05).Conclusion:The“Six-Step”Scenario-Based Teaching Method effectively enhances operating room students’mastery of theoretical knowledge,practical skills,and core comprehensive abilities,while significantly improving their teaching satisfaction.It warrants promotion and application in operating room nursing education.展开更多
We discuss the incomplete semi-iterative method (ISIM) for an approximate solution of a linear fixed point equations x=Tx+c with a bounded linear operator T acting on a complex Banach space X such that its resolvent h...We discuss the incomplete semi-iterative method (ISIM) for an approximate solution of a linear fixed point equations x=Tx+c with a bounded linear operator T acting on a complex Banach space X such that its resolvent has a pole of order k at the point 1. Sufficient conditions for the convergence of ISIM to a solution of x=Tx+c, where c belongs to the range space of R(I-T) k, are established. We show that the ISIM has an attractive feature that it is usually convergent even when the spectral radius of the operator T is greater than 1 and Ind 1T≥1. Applications in finite Markov chain is considered and illustrative examples are reported, showing the convergence rate of the ISIM is very high.展开更多
The Oral and maxillofacial region is one of the complex regions of the body considering the vast anatomical structures that are found in this region;head and neck surgery has potential for many complications, yet inad...The Oral and maxillofacial region is one of the complex regions of the body considering the vast anatomical structures that are found in this region;head and neck surgery has potential for many complications, yet inadequate information on occurrence of post-operative complications in oral and maxillofacial surgeries in our setting has been documented. The aim of this study was to determine the occurrence of common early post-operative complications after oral and maxillofacial surgery in relationship to the underlying systemic condition. A descriptive postoperative study was done whereby patients who underwent oral and maxillofacial surgery were included. The included patients were those who underwent surgery for different pathological conditions, trauma, developmental/congenital conditions and inflammatory conditions to mention few. Demographic data, complications developed within one week post operative, and underlying systemic comorbidities before and after surgery were documented and analysed. A total of 102 patients were included in the study. The mean age of participants was 30.00 ± 17.01 years with a range of 2 to 81 years. Majority 43.1% (n = 44) had benign tumors with a leading diagnosis of ameloblastoma. In general, the most common complications which were noted in the cases included Pain 98% (n = 100) and Post-operative Swelling 97.1% (n = 99). The presence of underlying systemic comorbid conditions has a significant role in occurrence of some severe complications. The occurrence of complications does increase the duration of stay in the hospital hence increasing cost of treatment for which bearers are both patients and the hospital.展开更多
We introduce multilevel augmentation methods for solving operator equations based on direct sum decompositions of the range space of the operator and the solution space of the operator equation and a matrix splitting ...We introduce multilevel augmentation methods for solving operator equations based on direct sum decompositions of the range space of the operator and the solution space of the operator equation and a matrix splitting scheme. We establish a general setting for the analysis of these methods, showing that the methods yield approximate solutions of the same convergence order as the best approximation from the subspace. These augmentation methods allow us to develop fast, accurate and stable nonconventional numerical algorithms for solving operator equations. In particular, for second kind equations, special splitting techniques are proposed to develop such algorithms. These algorithms are then applied to solve the linear systems resulting from matrix compression schemes using wavelet-like functions for solving Fredholm integral equations of the second kind. For this special case, a complete analysis for computational complexity and convergence order is presented. Numerical examples are included to demonstrate the efficiency and accuracy of the methods. In these examples we use the proposed augmentation method to solve large scale linear systems resulting from the recently developed wavelet Galerkin methods and fast collocation methods applied to integral equations of the secondkind. Our numerical results confirm that this augmentation method is particularly efficient for solving large scale linear systems induced from wavelet compression schemes.展开更多
This paper presents an elasto-viscoplastic consistent tangent operator (CTO) based boundary element formulation, and application for calculation of path-domain independentJ integrals (extension of the classicalJ integ...This paper presents an elasto-viscoplastic consistent tangent operator (CTO) based boundary element formulation, and application for calculation of path-domain independentJ integrals (extension of the classicalJ integrals) in nonlinear crack analysis. When viscoplastic deformation happens, the effective stresses around the crack tip in the nonlinear region is allowed to exceed the loading surface, and the pure plastic theory is not suitable for this situation. The concept of consistency employed in the solution of increment viscoplastic problem, plays a crucial role in preserving the quadratic rate asymptotic convergence of iteractive schemes based on Newton's method. Therefore, this paper investigates the viscoplastic crack problem, and presents an implicit viscoplastic algorithm using the CTO concept in a boundary element framework for path-domain independentJ integrals. Applications are presented with two numerical examples for viscoplastic crack problems andJ integrals.展开更多
An important problem in the eviluation of acupuncture has been the difficulty in defining and designingan appropriate control group.In order to examine our methodoly for a control group,patientswith one mandibular thi...An important problem in the eviluation of acupuncture has been the difficulty in defining and designingan appropriate control group.In order to examine our methodoly for a control group,patientswith one mandibular third molar extraction were randomly assigned to an acupuncture group or aplacebo acupuncture group.The following acupuncture points were used in which the needles werePlaced ipsilateral to the tooth extraction side:Hegu（LI4）,Jiache（ST 6）,Xiaguan（ST展开更多
In this paper,we consider the inverse problem for identifying the source term of the time-fractional equation with a hyper-Bessel operator.First,we prove that this inverse problem is ill-posed,and give the conditional...In this paper,we consider the inverse problem for identifying the source term of the time-fractional equation with a hyper-Bessel operator.First,we prove that this inverse problem is ill-posed,and give the conditional stability.Then,we give the optimal error bound for this inverse problem.Next,we use the fractional Tikhonov regularization method and the fractional Landweber iterative regularization method to restore the stability of the ill-posed problem,and give corresponding error estimates under different regularization parameter selection rules.Finally,we verify the effectiveness of the method through numerical examples.展开更多
In this paper,we propose a new analysis framework to study the linear convergence of relaxed operator splitting methods,which can be viewed as an extension of the classic Krasnosel'skii-Mann iteration and Banach-P...In this paper,we propose a new analysis framework to study the linear convergence of relaxed operator splitting methods,which can be viewed as an extension of the classic Krasnosel'skii-Mann iteration and Banach-Picard contraction.As applications,we derive the linear convergence of the generalized proximal point algorithm and the relaxed forward-backward splitting method in a simple and elegant way.展开更多
Based on the stress-strain data collected by a CSSMAS （container ship structure monitoring and analyzing system） onboard a container vessel, stress-strain responses of the ship＇s structure in high wave were analyze...Based on the stress-strain data collected by a CSSMAS （container ship structure monitoring and analyzing system） onboard a container vessel, stress-strain responses of the ship＇s structure in high wave were analyzed and illustrated for the identification of reasonable safe course sections. Besides the ship＇s structure safety, the maneuvering convenience is also deemed as a main concern which influences the safety of vessels in heavy waves. In order to develop a comprehensive guidance in adverse weather condition, the basic requirements on maneuvering convenience for vessels in storm were further discussed. In combination of the two requirements, namely structure health and maneuvering convenience, a proposed operational method was thus developed, which was an amendment to the traditional navigational method for ship in extreme weather. At the end of this paper, an example of optimal course planning in bad weather was illustrated by using the operational method proposed.展开更多
Reservoirs are an important part of China's infrastructure and play an important role in China's economic development. With the continuous development of society, the number of reservoirs has been increasing. ...Reservoirs are an important part of China's infrastructure and play an important role in China's economic development. With the continuous development of society, the number of reservoirs has been increasing. In some remote areas, the reservoir is not strictly controlled, thus it is potentially dangerous to the safety of the reservoir. When a dangerous situation occurs, it may seriously damage the lives and property of local residents. Therefore, it is necessary to strengthen the reservoir operation.展开更多
基金supported by the National Natural Science Foundation of China(No.50176051)the State Key Development Program for Basic Research of China(No.2000026306).
文摘Three experiments of static state storage method, low-temperature and constant-pressure storage method and low-temperature and constant-pressure storage method were carried out to investigate which method was best in gas hydrate. The relationships of hydrate rate, capacity and liquid temperature versus time were derived and three results were contrasted. The experimental results show lowtemperature and constant-pressure method is better than the other two methods because it's operation period is shorter and storage capacity is larger than the other two. Low-temperature and constant-pressure method is the best method. So new method will be new research objective.
文摘AIM: To establish a scoring system for predicting the incidence of postoperative complications and mortality in general surgery based on the physiological and operative severity score for the enumeration of mortality and morbidity (POSSUM), and to evaluate its efficacy. METHODS: Eighty-four patients with postoperative complications or death and 172 patients without postoperative complications, who underwent surgery in our department during the previous 2 years, were retrospectively analyzed by logistic regression. Fifteen indexes were investigated including age, cardiovascular function, respiratory function, blood test results, endocrine function, central nervous system function, hepatic function, renal function, nutritional status, extent of operative trauma, and course of anesthesia. Modified POSSUM (M-POSSUM) was developed using significant risk factors with its efficacy evaluated. RESULTS: The significant risk factors were found to be age, cardiovascular function, respiratory function, hepatic function, renal function, blood test results, endocrine function, nutritional status, duration of operation, intraoperative blood loss, and course of anesthesia. These factors were all included in the scoring system. There were significant differences in the scores between the patients with and without postoperative complications, between the patients died and survived with complications, and between the patients died and survived without complications. The receiver operating characteristic curves showed that the M-POSSUM could accurately predict postoperative complications and mortality.CONCLUSION: M-POSSUM correlates well with postoperative complications and mortality, and is more accurate than POSSUM.
文摘Introduction: Perioperative hypothermia in cardiac surgery is associated with adverse outcome. The aim of this investigation was to study whether an underbody forced-air warming blanket during coronary artery bypass graft surgery with normothermic cardiopulmonary bypass can prevent postoperative hypothermia. Methods: After Medical Ethics Committee approval, 60 low-risk cardiac surgery patients at random were assigned into a group that received standard thermal care management (control group n = 30) and a group that received the underbody forced-air warming system plus the standard thermal care (intervention group n = 30). Results: The temperature after-drop from the end of cardiopulmonary bypass to arrival in the ICU was less in the intervention group versus control group (0.4°C ± 0.3°C vs 0.6°C ± 0.4°C;P = 0.027). Out of the intervention group, 27 patients arrived in the ICU with a bladder temperature ? 36°C (90%) as compared to 14 patients (46.7%) from the control group (P < 0.001). The peripheral temperature was significantly higher in the intervention group as compared to the control group (P < 0.001). Conclusions: A full underbody forced-air warming blanket prevents postoperative hypothermia in normothermic coronary artery bypass graft surgery patients.
文摘In this paper, a modified Newton type iterative method is considered for ap- proximately solving ill-posed nonlinear operator equations involving m-accretive mappings in Banach space. Convergence rate of the method is obtained based on an a priori choice of the regularization parameter. Our analysis is not based on the sequential continuity of the normalized duality mapping.
基金supported by Sichuan Science and Technology Program(No.24NSFSC4579)National Natural Science Foundation of China(No.12305193)+2 种基金Sichuan Science and Technology Program(No.23NSFSC6149)National Natural Science Foundation of China(No.12305194)Technology on Reactor System Design Technology Laboratory Stable support Funding(No.2023_JCJQ_LB_003).
文摘The Stirling engine,as a closed-cycle power machine,exhibits excellent emission characteristics and broad energy adaptability.Second-order analysis methods are extensively used during the foundational design and thermodynamic examination of Stirling engines,owing to their commendable model precision and remarkable efficiency.To scrutinize the effect of Stirling engine design parameters on the cyclical work output and efficiency,this study formulates a series of differential equations for the Stirling cycle by employing second-order analysis methods,subsequently augmenting the predictive accuracy by integrating considerations of loss mechanisms.In addition,an iterative method for the convergence of the average pressure was introduced.The predictive capability of the established model was validated using GPU-3 and RE-1000 experimental data.According to the model,parameters such as the operational fluid,porosity of the regenerator,and diameter of the wire mesh and their influence on the resulting work output and cyclic efficiency of the Stirling engine were analyzed,thereby facilitating a broader understanding of the engine's functional characteristics.These findings suggest that hydrogen,owing to its lower dynamic viscosity coefficient,can provide superior output power.The loss due to flow resistance tends to increase with the rotational speed.Additionally,under conditions of elevated rotational speed,the loss from flow resistance declines in cases of increased porosity,and the enhancement of the porosity to diminish flow resistance losses can boost both the output work and the cyclic efficiency of the engine.As the porosity increased further,the hydraulic diameter and dead volume in the regenerator continued to expand,causing the pressure drop within the engine to become the dominant factor in the gradual reduction of output power.Furthermore,extending the length of the regenerator results in a decrease in the output work,although the thermal cycle efficiency initially increases before eventually decreasing.Based on these insights,this study pursues the optimal designs for Stirling engines.
基金Supported by the National Natural Science Foundation of China (10371082)Chinese National Natural Science Foundation Committee Tianyuan Foundation (10526040)Guangzhou University Doctor Foundation (WXF-1001)
文摘The convergence of several Galerkin-Petrov methods, including polynomial collocation and analytic element collocation methods of Toeplitz operators on Dirichlet space, is established. In particular, it is shown that such methods converge if the basis and test function own certain circular symmetry.
基金The NSF(0611005)of Jiangxi Province and the SF(2007293)of Jiangxi Provincial Education Department.
文摘In this paper we develop two multilevel iteration methods for solving linear systems resulting from the Galerkin method and Tikhonov regularization for linear ill-posed problems. The two algorithms and their convergence analyses are presented in an abstract framework.
文摘Objective:While a rushed operation can omit essential procedures,prolonged operative time results in higher morbidity.Nevertheless,the optimal operative time range remains uncertain.This study aimed to estimate the ideal operative time range and evaluate its applicability in laparoscopic cancer surgery.Methods:A prospectively collected multicenter database of 397 patients who underwent laparoscopic distal gastrectomy were retrospectively reviewed.The ideal operative time range was statistically calculated by separately analyzing the operative time of uneventful surgeries.Finally,intraoperative and postoperative outcomes were compared among the shorter,ideal,and longer operative time groups.Results:The statistically calculated ideal operative time was 135.4-165.4 min.The longer operative time(LOT)group had a lower rate of uneventful,perfect surgery than the ideal or shorter operative time(IOT/SOT)group(2.8%vs.8.8%and 2.2%vs.13.4%,all P<0.05).Longer operative time increased bleeding,postoperative morbidities,and delayed diet and discharge(all P<0.05).Particularly,an uneventful,perfect surgery could not be achieved when the operative time exceeded 240 min.Regardless of ideal time range,SOT group achieved the highest percentage of uneventful surgery(13.4%),which was possible by surgeon's ability to retrieve a higher number of lymph nodes and perform≥150 gastrectomies annually.Conclusions:Operative time longer than the ideal time range(especially≥240 min)should be avoided.If the essential operative procedure were faithfully conducted without compromising oncological safety,an operative time shorter than the ideal range leaded to a better prognosis.Efforts to minimize operative time should be attempted with sufficient surgical experience.
基金Scientific Research Programme for Health Commission of Jiangxi Province,No.20204269.
文摘BACKGROUND As one of the major abdominal operations,pancreaticoduodenectomy(PD)involves many organs.The operation is complex,and the scope of the operation is large,which can cause significant trauma in patients.The operation has a high rate of complications.Pancreatic leakage is the main complication after PD.When pancreatic leakage occurs after PD,it can often lead to abdominal bleeding and infection,threatening the lives of patients.One study found that pancreatic leakage was affected by many factors including the choice of pancreaticojejunostomy method which can be well controlled.AIM To investigate the choice of operative methods for pancreaticojejunostomy and to conduct a multivariate study of pancreatic leakage in PD.METHODS A total of 420 patients undergoing PD in our hospital from January 2014 to March 2019 were enrolled and divided into group A(n=198)and group B(n=222)according to the pancreatointestinal anastomosis method adopted during the operation.Duct-to-mucosa pancreatojejunostomy was performed in group A and bundled pancreaticojejunostomy was performed in group B.The operation time,intraoperative blood loss,and pancreatic leakage of the two groups were assessed.The occurrence of pancreatic leakage after the operation in different patients was analyzed.RESULTS The differences in operative time and intraoperative bleeding between groups A and B were not significant(P>0.05).In group A,the time of pancreatojejunostomy was 26.03±4.40 min and pancreatic duct diameter was 3.90±1.10 mm.These measurements were significantly higher than those in group B(P<0.05).The differences in the occurrence of pancreatic leakage,abdominal infection,abdominal hemorrhage and gastric retention between group A and group B were not significant(P>0.05).The rates of pancreatic leakage in patients with preoperative albumin<30 g/L,preoperative jaundice time≥8 wk,and pancreatic duct diameter<3 mm,were 23.33%,33.96%,and 19.01%,respectively.These were significantly higher than those in patients with preoperative albumin≥30 g/L,preoperative jaundice time<8 wk,and pancreatic duct diameter≥3 cm(P<0.05).Logistic regression analysis showed that preoperative albumin<30 g/L,preoperative jaundice time≥8 wk,and pancreatic duct diameter<3 mm were risk factors for pancreatic leakage after PD(odds ratio=2.038,2.416 and 2.670,P<0.05).CONCLUSION The pancreatointestinal anastomosis method during PD has no significant effect on the occurrence of pancreatic leakage.The main risk factors for pancreatic leakage include preoperative albumin,preoperative jaundice time,and pancreatic duct diameter.
基金This work was supported by the National Natural Science Foundation of China(No.11971354)The author Yi-Shu Du acknowledges the financial support from the China Scholarship Council(File No.201906260146).
文摘After discretization by the finite volume method,the numerical solution of fractional diffusion equations leads to a linear system with the Toeplitz-like structure.The theoretical analysis gives sufficient conditions to guarantee the positive-definite property of the discretized matrix.Moreover,we develop a class of positive-definite operator splitting iteration methods for the numerical solution of fractional diffusion equations,which is unconditionally convergent for any positive constant.Meanwhile,the iteration methods introduce a new preconditioner for Krylov subspace methods.Numerical experiments verify the convergence of the positive-definite operator splitting iteration methods and show the efficiency of the proposed preconditioner,compared with the existing approaches.
文摘Objective:To explore the application effectiveness of the“Six-Step”Scenario-Based Teaching Method in operating room nursing education.Methods:Seventy nursing students undergoing clinical training in the operating room of a certain hospital from January 2024 to June 2025 were selected.They were randomly divided into an observation group(n=35)and a control group(n=35)using a random number table.The control group received traditional“mentor-apprentice”on-the-job training,while the observation group underwent the“six-step”scenario-based teaching method.The two groups were compared on final assessment scores,comprehensive competency,surgical nursing emergency response ability,and teaching satisfaction indicators.Results:The observation group achieved significantly higher final assessment scores(85.54±5.05)than the control group(78.63±4.75);After instruction,the observation group scored significantly higher than the control group in:mastery of basic duties and procedures(4.22±0.30 vs.3.98±0.30),understanding of surgical nursing essentials(4.39±0.19 vs.3.98±0.30),proficiency in surgical assistance(4.11±0.33 vs.3.98±0.30),aseptic awareness(4.32±0.24 vs.3.98±0.30),risk awareness(4.22±0.17 vs.3.98±0.30),and occupational safety awareness(4.01±0.23 vs.3.98±0.30).(4.01±0.23),which were significantly higher than the control group’s scores(3.36±0.28),(3.14±0.27),(3.29±0.24),(3.53±0.36),(3.17±0.25),and(3.51±0.18),respectively.Students in the observation group scored significantly higher than the control group in emergency hands-on skills(24.53±1.85 points),surgical coordination skills(27.65±1.87 points),emergency coordination skills(25.34±1.83 points),and patient condition observation skills(24.34±1.79 points)were significantly higher than those of the control group(20.78±1.74 points,26.31±1.95 points,22.92±1.69 points,and 21.58±1.77 points,respectively).The satisfaction rate with operating room nursing education among students in the observation group(97.00%)was significantly higher than that in the control group(77.00%).All differences were statistically significant(p<0.05).Conclusion:The“Six-Step”Scenario-Based Teaching Method effectively enhances operating room students’mastery of theoretical knowledge,practical skills,and core comprehensive abilities,while significantly improving their teaching satisfaction.It warrants promotion and application in operating room nursing education.
基金Project1 990 1 0 0 6 supported by National Natural Science Foundation of China,Doctoral Foundation of China,Chi-na Scholarship council and Laboratory of Computational Physics in Beijing of Chinathe second author is also supportedby the State Major Key
文摘We discuss the incomplete semi-iterative method (ISIM) for an approximate solution of a linear fixed point equations x=Tx+c with a bounded linear operator T acting on a complex Banach space X such that its resolvent has a pole of order k at the point 1. Sufficient conditions for the convergence of ISIM to a solution of x=Tx+c, where c belongs to the range space of R(I-T) k, are established. We show that the ISIM has an attractive feature that it is usually convergent even when the spectral radius of the operator T is greater than 1 and Ind 1T≥1. Applications in finite Markov chain is considered and illustrative examples are reported, showing the convergence rate of the ISIM is very high.
文摘The Oral and maxillofacial region is one of the complex regions of the body considering the vast anatomical structures that are found in this region;head and neck surgery has potential for many complications, yet inadequate information on occurrence of post-operative complications in oral and maxillofacial surgeries in our setting has been documented. The aim of this study was to determine the occurrence of common early post-operative complications after oral and maxillofacial surgery in relationship to the underlying systemic condition. A descriptive postoperative study was done whereby patients who underwent oral and maxillofacial surgery were included. The included patients were those who underwent surgery for different pathological conditions, trauma, developmental/congenital conditions and inflammatory conditions to mention few. Demographic data, complications developed within one week post operative, and underlying systemic comorbidities before and after surgery were documented and analysed. A total of 102 patients were included in the study. The mean age of participants was 30.00 ± 17.01 years with a range of 2 to 81 years. Majority 43.1% (n = 44) had benign tumors with a leading diagnosis of ameloblastoma. In general, the most common complications which were noted in the cases included Pain 98% (n = 100) and Post-operative Swelling 97.1% (n = 99). The presence of underlying systemic comorbid conditions has a significant role in occurrence of some severe complications. The occurrence of complications does increase the duration of stay in the hospital hence increasing cost of treatment for which bearers are both patients and the hospital.
基金Supported in part by the Natural Science Foundation of China under grants 10371137and 10201034Foundation of Doctoral Program of National Higher Education of China under under grant 20030558008Guangdong Provincial Natural Science Foundation of China u
文摘We introduce multilevel augmentation methods for solving operator equations based on direct sum decompositions of the range space of the operator and the solution space of the operator equation and a matrix splitting scheme. We establish a general setting for the analysis of these methods, showing that the methods yield approximate solutions of the same convergence order as the best approximation from the subspace. These augmentation methods allow us to develop fast, accurate and stable nonconventional numerical algorithms for solving operator equations. In particular, for second kind equations, special splitting techniques are proposed to develop such algorithms. These algorithms are then applied to solve the linear systems resulting from matrix compression schemes using wavelet-like functions for solving Fredholm integral equations of the second kind. For this special case, a complete analysis for computational complexity and convergence order is presented. Numerical examples are included to demonstrate the efficiency and accuracy of the methods. In these examples we use the proposed augmentation method to solve large scale linear systems resulting from the recently developed wavelet Galerkin methods and fast collocation methods applied to integral equations of the secondkind. Our numerical results confirm that this augmentation method is particularly efficient for solving large scale linear systems induced from wavelet compression schemes.
基金The project supported by National Natural Science Foundation of China(9713008)Zhejiang Natural Science Foundation Special Funds No. RC.9601
文摘This paper presents an elasto-viscoplastic consistent tangent operator (CTO) based boundary element formulation, and application for calculation of path-domain independentJ integrals (extension of the classicalJ integrals) in nonlinear crack analysis. When viscoplastic deformation happens, the effective stresses around the crack tip in the nonlinear region is allowed to exceed the loading surface, and the pure plastic theory is not suitable for this situation. The concept of consistency employed in the solution of increment viscoplastic problem, plays a crucial role in preserving the quadratic rate asymptotic convergence of iteractive schemes based on Newton's method. Therefore, this paper investigates the viscoplastic crack problem, and presents an implicit viscoplastic algorithm using the CTO concept in a boundary element framework for path-domain independentJ integrals. Applications are presented with two numerical examples for viscoplastic crack problems andJ integrals.
文摘An important problem in the eviluation of acupuncture has been the difficulty in defining and designingan appropriate control group.In order to examine our methodoly for a control group,patientswith one mandibular third molar extraction were randomly assigned to an acupuncture group or aplacebo acupuncture group.The following acupuncture points were used in which the needles werePlaced ipsilateral to the tooth extraction side:Hegu（LI4）,Jiache（ST 6）,Xiaguan（ST
基金supported by the National Natural Science Foundation of China(11961044)the Doctor Fund of Lan Zhou University of Technologythe Natural Science Foundation of Gansu Provice(21JR7RA214)。
文摘In this paper,we consider the inverse problem for identifying the source term of the time-fractional equation with a hyper-Bessel operator.First,we prove that this inverse problem is ill-posed,and give the conditional stability.Then,we give the optimal error bound for this inverse problem.Next,we use the fractional Tikhonov regularization method and the fractional Landweber iterative regularization method to restore the stability of the ill-posed problem,and give corresponding error estimates under different regularization parameter selection rules.Finally,we verify the effectiveness of the method through numerical examples.
基金Supported by the National Natural Science Foundation of China(Grant Nos.1180145511871059+4 种基金11971238)China Postdoctoral Science Foundation(Grant Nos.2019M6634592020T130081)the Applied Basic Project of Sichuan Province(Grant No.2020YJ0111)the Open Project of Key Laboratory of School of Mathematical Sciences,Chongqing Normal University(Grant No.CSSXKFKTM202004)。
文摘In this paper,we propose a new analysis framework to study the linear convergence of relaxed operator splitting methods,which can be viewed as an extension of the classic Krasnosel'skii-Mann iteration and Banach-Picard contraction.As applications,we derive the linear convergence of the generalized proximal point algorithm and the relaxed forward-backward splitting method in a simple and elegant way.
文摘Based on the stress-strain data collected by a CSSMAS （container ship structure monitoring and analyzing system） onboard a container vessel, stress-strain responses of the ship＇s structure in high wave were analyzed and illustrated for the identification of reasonable safe course sections. Besides the ship＇s structure safety, the maneuvering convenience is also deemed as a main concern which influences the safety of vessels in heavy waves. In order to develop a comprehensive guidance in adverse weather condition, the basic requirements on maneuvering convenience for vessels in storm were further discussed. In combination of the two requirements, namely structure health and maneuvering convenience, a proposed operational method was thus developed, which was an amendment to the traditional navigational method for ship in extreme weather. At the end of this paper, an example of optimal course planning in bad weather was illustrated by using the operational method proposed.
文摘Reservoirs are an important part of China's infrastructure and play an important role in China's economic development. With the continuous development of society, the number of reservoirs has been increasing. In some remote areas, the reservoir is not strictly controlled, thus it is potentially dangerous to the safety of the reservoir. When a dangerous situation occurs, it may seriously damage the lives and property of local residents. Therefore, it is necessary to strengthen the reservoir operation.
