A new algorithm based on an FC-tree （frequent closed pattern tree） and a max-FCIA （maximal frequent closed itemsets algorithm） is presented, which is used to mine the frequent closed itemsets for solving memory an...A new algorithm based on an FC-tree （frequent closed pattern tree） and a max-FCIA （maximal frequent closed itemsets algorithm） is presented, which is used to mine the frequent closed itemsets for solving memory and time consuming problems. This algorithm maps the transaction database by using a Hash table,gets the support of all frequent itemsets through operating the Hash table and forms a lexicographic subset tree including the frequent itemsets.Efficient pruning methods are used to get the FC-tree including all the minimum frequent closed itemsets through processing the lexicographic subset tree.Finally,frequent closed itemsets are generated from minimum frequent closed itemsets.The experimental results show that the mapping transaction database is introduced in the algorithm to reduce time consumption and to improve the efficiency of the program.Furthermore,the effective pruning strategy restrains the number of candidates,which saves space.The results show that the algorithm is effective.展开更多
Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells ...Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.展开更多
Rationally regulating the porosity of hard carbon(HC),especially the closed pores matching the low potential plateau and the ultra-microporous structure suitable for Na+embedding,has been shown to be the key to improv...Rationally regulating the porosity of hard carbon(HC),especially the closed pores matching the low potential plateau and the ultra-microporous structure suitable for Na+embedding,has been shown to be the key to improving the sodium storage performance and initial coulombic efficiency(ICE).However,the preparation of such HC materials with specific pore structures still faces great challenges.Herein,a simple pre-oxidation strategy is employed to construct abundant closed ultra-microporous structures in soy protein powder-derived HC material,achieving a significant improvement in its ICE and platform capacity.The pre-oxidation process promotes the cross-linking degree of the soy protein,thereby hindering the directional growth of graphite domains during the carbonization process.The optimized HC exhibits ultra-high platform capacity(329 mAh g^(-1))and considerable energy density(148.5 Wh kg^(-1)).Based on the ex-situ Raman and X-ray photoelectron spectroscopy characterization results,the excellent sodium storage capacity of the HC material is attributed to the synergistic effect of adsorption-intercalation/filling.The presented work provides novel insights into the synthesis of other biomass-derived HC materials with abundant closed ultra-micro pores.展开更多
Objectives:Suicidal ideation(SI)among university students is a growing concern,influenced by anxiety,depression,and bullying.However,family closeness and peer support may act as protective factors,reducing the risk of...Objectives:Suicidal ideation(SI)among university students is a growing concern,influenced by anxiety,depression,and bullying.However,family closeness and peer support may act as protective factors,reducing the risk of SI.Therefore,this study aims to investigate the key factors influencing SI among university students,focusing on the effects of anxiety,depression,and bullying,along with the roles of family closeness and peer support.The research also explores the interactions and mechanisms between these variables.Methods:A sample of 318 university students was surveyed,evaluating six main factors:anxiety,depression,bullying,family closeness,peer support,and SI.Using the Structural Equation Modeling(SEM)and Artificial Neural Networks(ANN)approach,both compensatory and non-compensatory relationships were examined.Results:Anxiety,depression,and bullying significantly contribute to SI,with depression mediating the link between anxiety,bullying,and SI.Additionally,family closeness moderates the effects of anxiety and bullying on SI,while peer supportmoderates the effects of depression and bullying.Themultilayer perceptron analysis identifies peer support as the most influential predictor,followed by bullying,family closeness,depression,and anxiety.Conclusion:The study identifies anxiety,depression,and bullying as key factors influencing suicidal ideation(SI)among university students.Family closeness and peer support act as protective factors,moderating the effects of these variables on SI.展开更多
Hard carbon(HC)is considered the most promising anode material for sodium-ion batteries(SIBs)due to its high costeffectiveness and outstanding overall performance.However,the amorphous and intricate microstructure of ...Hard carbon(HC)is considered the most promising anode material for sodium-ion batteries(SIBs)due to its high costeffectiveness and outstanding overall performance.However,the amorphous and intricate microstructure of HC poses significant challenges in elucidating the structure-performance relationship,which has led to persistent misinterpretations regarding the intrinsic characteristics of closed pores.An irrational construction methodology of closed pores inevitably results in diminished plateau capacity,which severely restricts the practical application of HC in high-energy-density scenarios.This review provides a systematic exposition of the conceptual framework and origination mechanisms of closed pores,offering critical insights into their structural characteristics and formation pathways.Subsequently,by correlating lattice parameters with defect configurations,the structure-performance relationships governing desolvation kinetics and sodium storage behavior are rigorously established.Furthermore,pioneering advancements in structural engineering are critically synthesized to establish fundamental design principles for the rational modulation of closed pores in HC.It is imperative to emphasize that adopting a molecular-level perspective,coupled with a synergistic kinetic/thermodynamic approach,is critical for understanding and controlling the transformation process from open pores to closed pores.These innovative perspectives are strategically designed to accelerate the commercialization of HC,thereby catalyzing the sustainable and high-efficiency development of SIBs.展开更多
Loess is susceptible to loading effects such as significant changes in strength and volume variation caused by loading and wetting.In this study,considering the different connection states of pore water and gas in loe...Loess is susceptible to loading effects such as significant changes in strength and volume variation caused by loading and wetting.In this study,considering the different connection states of pore water and gas in loess fabric,the gas phase closure case is incorporated into a unified form of the generalized effective stress framework,introducing a damage parameter considering the effects of closed pore gas.The loading effects of unsaturated loess under wide variations in saturation are described in a unified way,and the model performance is verified by corresponding stress and hydraulic path tests.The results indicated that the collapse response involves the initial void ratio of loess,and the coupled outwards motion of the loading-collapse(LC)yield surface under loading enhances its structural strength.Suction-enhanced yield stress requires a greater"tensile stress"to counteract its structural stability.The nucleation of bubbles at high saturation causes a decrease in yield stress.The loading effect exhibits a smaller collapse behavior when the influence of closed gas is considered,whereas the suction path does not cross the LC in the stress space under hydraulic action for the same parameters,which amplifies the influence of closed gas on loess deformation.展开更多
In conventional piezoelectric micromachined ultrasonic transducers(PMUTs),the backside acoustic energy is often used inefficiently,resulting in up to half of the energy being wasted.Vacuum encapsulation can improve th...In conventional piezoelectric micromachined ultrasonic transducers(PMUTs),the backside acoustic energy is often used inefficiently,resulting in up to half of the energy being wasted.Vacuum encapsulation can improve the energy utilization efficiency,but this technique is not compatible with state-of-the-art devices such as cantilever-based PMUTs.A closed back cavity provides an alternative method for effectively utilizing the backside acoustic energy.This paper investigates the effects of a closed back cavity on PMUT performance through theoretical analysis,simulations,and experimental verification.Increasing the cavity depth produces a periodic modulation of several key PMUT metrics,such as the relative frequency deviation and quality factor.The optimal cavity depth for PMUTs that ensures a robust resonant frequency and high quality factor is defined as a function of the acoustic wavelength.A closed back cavity also provides an effective method for continuously tuning the quality factor,and thus the bandwidth,of PMUTs.This work paves the way for air-coupled PMUTs with adjustable performance for various applications.展开更多
Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of s...Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of surgical failure.Therefore,it is necessary to design a visualization system for closed thoracic drainage.Augmented reality(AR)technology can assist in visualizing the internal anatomical structure and determining the insertion point on the body surface.The structure of the currently used steel-needle-guided chest tube was modified by integrating it with an ultrafine diameter camera to provide real-time visualization of the puncture process.After simulation experiments,the overall registration error of the AR method was measured to be within(3.59±0.53)mm,indicating its potential for clinical application.The ultrafine diameter camera module and improved steel-needle-guided chest tube can timely reflect the position of the needle tip in the human body.A comparative experiment showed that video guidance could improve the safety of the puncture process compared to the traditional method.Finally,a qualitative evaluation of the usability of the system was conducted through a questionnaire.This system facilitates the visualization of closed thoracic drainage puncture procedure and pro-vides an implementation scheme to enhance the accuracy and safety of the operative step,which is conducive to reducing the learning curve and improving the proficiency of the doctors.展开更多
A binary complete decision table with many-valued decisions is a table with n attributes and 2^(n) pairwise distinct rows filled with numbers from the set{0,1}.Each row of this table is labeled with a nonempty finite ...A binary complete decision table with many-valued decisions is a table with n attributes and 2^(n) pairwise distinct rows filled with numbers from the set{0,1}.Each row of this table is labeled with a nonempty finite set of decisions.For a given row of the table,the task is to find a decision from the set of decisions attached to the row.Such tables are generalizations of Boolean functions.They can also be viewed as representations of various problems related to systems of decision rules.In this paper,we consider three types of classes of binary complete decision tables with many-valued decisions,closed with respect to removal of columns and changing of decisions.For tables from these classes,we study the relationships between the minimum weighted depth of deterministic,nondeterministic,and(for one type of classes)strongly nondeterministic decision trees and the total weight of attributes attached to columns.Note that nondeterministic decision trees and strongly nondeterministic decision trees for decision tables can be interpreted as a way of representing the two types of systems of decision rules for these tables.展开更多
Objective Close reduction and internal fixation have gained popularity for the treatment of pelvic fractures.However,the closed reduction of bilateral displaced posterior pelvic ring disruption is a great challenge ev...Objective Close reduction and internal fixation have gained popularity for the treatment of pelvic fractures.However,the closed reduction of bilateral displaced posterior pelvic ring disruption is a great challenge even for the most experienced surgeon.In this study,we describe in detail a novel unlocking closed reduction technique(UCRT)frame that allows strong traction for bilateral posterior pelvic ring displacement and presents preliminary clinical outcomes.Methods We retrospectively reviewed 32 patients with bilateral displaced posterior pelvic ring disruptions(AO/OTA 61-C2 and C3)who were initially treated with this technique between July 2017 and July 2022.According to the AO/OTA clas-sification,there were 9 cases(28.12%)of 61-C2,and 23 cases(71.88%)of 61-C3.There were 11 males,21 females,with an average age of 38.1 years.The interval from injury to operation was 4-27 days,with a cut-off of 12.5 days(receiver operat-ing characteristic curve).Operative time,blood loss,and postoperative radiographic findings were recorded.The functional outcomes and complications were followed.Results A total of 30(93.8%)patients achieved successful closed reduction,whereas 2 required open reduction.The success-ful closed reduction rate was 95.5%(21/22)in patients whose injury-to-operation time was less than 12.5 days.The vertical displacement percent correction of the obviously displaced hemipelvis was 70.20%±16.79%on average.The average degree of pelvic deformity correction was 64.86%±17.71%.Thirty patients were followed up for at least 12 months(12-36 months),and no complications of nonunion or redisplacement were observed.The Matta-Tornetta scoring standard revealed that the excellent(25/30)and good(4/30)rate was 96.7%.The Majeed clinical efficacy score revealed that the overall excellent and good rate was 100%.One patient had INFIX-related infection,and 2 reported numbness in the lateral thigh.The numbness was improved after INFIX removal.Conclusions This study presents an updated technique for closed reduction using a UCRT frame for bilateral posterior pelvic ring disruption,which has been shown to be effective,as indicated by excellent surgical and functional outcomes.展开更多
In this article,we are concerned with the C^(2)estimates for the k-convex solutions of a class of degenerate k-Hessian equations on closed Hermitian manifolds,whose function in the right-hand side is relevant to the u...In this article,we are concerned with the C^(2)estimates for the k-convex solutions of a class of degenerate k-Hessian equations on closed Hermitian manifolds,whose function in the right-hand side is relevant to the unknown function and its gradient.We will get C^(0)estimate by promoting others′results,and get the“HMW estimate”of this equation such that the conditions of using blow-up analysis are satisfied,and the gradient estimate and second-order estimate will be obtained.Such an estimate will be helpful to study the existence for the solution of the equation.展开更多
We present the essential stellar parameters of the close visual triple system HD 2893 using Al-Wardat's method for analyzing binary and multiple star systems in conjunction with Kurucz's model atmospheres.This...We present the essential stellar parameters of the close visual triple system HD 2893 using Al-Wardat's method for analyzing binary and multiple star systems in conjunction with Kurucz's model atmospheres.This method accurately computes the spectrophotometric stellar masses through a combined synthetic spectral energy distribution approach that compares the results with observed data.The vigorous approach uses spectroscopic,photometric,and dynamical analysis to yield precise results.The method implements Gaia DR3 measurements and other measurements like those of Hipparcos and 2MASS All-Sky Catalog as a guide for the best fit between the synthetic spectra and observed photometry.The analysis gives precise spectrophotometric stellar masses for the system being M_(Sph)^(A)=1.20±0.07M⊙,M_(Sph)^(B)=1.09±0.06M⊙,and M_(Sph)^(C)=0.46±0.01M⊙.It shows that the three components are main sequence stars with an estimated age of around 1.0 Gyr.When integrated with the dynamical analysis,a new dynamical parallax for the system is obtained,π_(dyn)=13.8528±0.20 mas.Additionally,the discussion covers the formation and evolution of the triple system.展开更多
An analytic function f in the unit disk D ：= {z ∈ C ： ｜z｜ 〈 1}, standardly normalized, is called close-to-convex with respect to the Koebe function k（z） ：= z/（1-z）2, z ∈ D, if there exists δ ∈ （-π/2,...An analytic function f in the unit disk D ：= {z ∈ C ： ｜z｜ 〈 1}, standardly normalized, is called close-to-convex with respect to the Koebe function k（z） ：= z/（1-z）2, z ∈ D, if there exists δ ∈ （-π/2,π/2） such that Re {eiδ（1-z）2f′（z）} 〉 0, z ∈ D. For the class C（k） of all close-to-convex functions with respect to k, related to the class of functions convex in the positive direction of the imaginary axis, the Fekete-Szego problem is studied.展开更多
Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a math...Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a mathematical model of a multi-objective assessment of a long span suspension bridge is set up. An example is given to show the procedure in the synthetical condition assessment of the Runyang Suspension Bridge, which includes the hierarchical division, the definition of factor weights and fuzzy membership functions, and the calculation of closeness degrees, etc. The assessment combines both the data from the health monitoring system and the manual tests. The classification of evaluation items as well as the calculation of deterministic and nondeterministic items is presented. Compared with the traditional method of point rating, this method can better describe the discreteness of monitoring data and the fuzziness in the condition assessment.展开更多
Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and ...Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and Conclusion The criteria for singular points, closed orbits and hyperbolic equilibrium points of a second order autonomous Birkhoff system are given. Moreover the stability of equilibria, stable manifolds and unstable manifolds are obtained.展开更多
基金The National Natural Science Foundation of China(No.60603047)the Natural Science Foundation of Liaoning ProvinceLiaoning Higher Education Research Foundation(No.2008341)
文摘A new algorithm based on an FC-tree （frequent closed pattern tree） and a max-FCIA （maximal frequent closed itemsets algorithm） is presented, which is used to mine the frequent closed itemsets for solving memory and time consuming problems. This algorithm maps the transaction database by using a Hash table,gets the support of all frequent itemsets through operating the Hash table and forms a lexicographic subset tree including the frequent itemsets.Efficient pruning methods are used to get the FC-tree including all the minimum frequent closed itemsets through processing the lexicographic subset tree.Finally,frequent closed itemsets are generated from minimum frequent closed itemsets.The experimental results show that the mapping transaction database is introduced in the algorithm to reduce time consumption and to improve the efficiency of the program.Furthermore,the effective pruning strategy restrains the number of candidates,which saves space.The results show that the algorithm is effective.
基金supported by the National Natural Science Foundation of China,Nos.82271397(to MG),82001293(to MG),82171355(to RX),81971295(to RX),and 81671189(to RX)。
文摘Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury.
基金supported by the National Natural Science Foundation of China(42167068,22269020)the Gansu Province Higher Education Industry Support Plan Project(2023CYZC-68)the Central Guidance for Local Science and Technology Development Funds Project(YDZX20216200001007)。
文摘Rationally regulating the porosity of hard carbon(HC),especially the closed pores matching the low potential plateau and the ultra-microporous structure suitable for Na+embedding,has been shown to be the key to improving the sodium storage performance and initial coulombic efficiency(ICE).However,the preparation of such HC materials with specific pore structures still faces great challenges.Herein,a simple pre-oxidation strategy is employed to construct abundant closed ultra-microporous structures in soy protein powder-derived HC material,achieving a significant improvement in its ICE and platform capacity.The pre-oxidation process promotes the cross-linking degree of the soy protein,thereby hindering the directional growth of graphite domains during the carbonization process.The optimized HC exhibits ultra-high platform capacity(329 mAh g^(-1))and considerable energy density(148.5 Wh kg^(-1)).Based on the ex-situ Raman and X-ray photoelectron spectroscopy characterization results,the excellent sodium storage capacity of the HC material is attributed to the synergistic effect of adsorption-intercalation/filling.The presented work provides novel insights into the synthesis of other biomass-derived HC materials with abundant closed ultra-micro pores.
文摘A survey of recent progress on the multiplicity and stability problems for closed characteristics on compact convex hypersurfaces in R^(2n) is given.
文摘Objectives:Suicidal ideation(SI)among university students is a growing concern,influenced by anxiety,depression,and bullying.However,family closeness and peer support may act as protective factors,reducing the risk of SI.Therefore,this study aims to investigate the key factors influencing SI among university students,focusing on the effects of anxiety,depression,and bullying,along with the roles of family closeness and peer support.The research also explores the interactions and mechanisms between these variables.Methods:A sample of 318 university students was surveyed,evaluating six main factors:anxiety,depression,bullying,family closeness,peer support,and SI.Using the Structural Equation Modeling(SEM)and Artificial Neural Networks(ANN)approach,both compensatory and non-compensatory relationships were examined.Results:Anxiety,depression,and bullying significantly contribute to SI,with depression mediating the link between anxiety,bullying,and SI.Additionally,family closeness moderates the effects of anxiety and bullying on SI,while peer supportmoderates the effects of depression and bullying.Themultilayer perceptron analysis identifies peer support as the most influential predictor,followed by bullying,family closeness,depression,and anxiety.Conclusion:The study identifies anxiety,depression,and bullying as key factors influencing suicidal ideation(SI)among university students.Family closeness and peer support act as protective factors,moderating the effects of these variables on SI.
基金supported by the National Natural Science Foundation of China(22379165,U21A20284)Natural Science Foundation of Hunan Province(2023JJ40704).
文摘Hard carbon(HC)is considered the most promising anode material for sodium-ion batteries(SIBs)due to its high costeffectiveness and outstanding overall performance.However,the amorphous and intricate microstructure of HC poses significant challenges in elucidating the structure-performance relationship,which has led to persistent misinterpretations regarding the intrinsic characteristics of closed pores.An irrational construction methodology of closed pores inevitably results in diminished plateau capacity,which severely restricts the practical application of HC in high-energy-density scenarios.This review provides a systematic exposition of the conceptual framework and origination mechanisms of closed pores,offering critical insights into their structural characteristics and formation pathways.Subsequently,by correlating lattice parameters with defect configurations,the structure-performance relationships governing desolvation kinetics and sodium storage behavior are rigorously established.Furthermore,pioneering advancements in structural engineering are critically synthesized to establish fundamental design principles for the rational modulation of closed pores in HC.It is imperative to emphasize that adopting a molecular-level perspective,coupled with a synergistic kinetic/thermodynamic approach,is critical for understanding and controlling the transformation process from open pores to closed pores.These innovative perspectives are strategically designed to accelerate the commercialization of HC,thereby catalyzing the sustainable and high-efficiency development of SIBs.
基金funded by the National Natural Science Foundation of China (Grant Nos.42230712,42472357)the China Postdoctoral Science Foundation (Grant No.2023MD734211).
文摘Loess is susceptible to loading effects such as significant changes in strength and volume variation caused by loading and wetting.In this study,considering the different connection states of pore water and gas in loess fabric,the gas phase closure case is incorporated into a unified form of the generalized effective stress framework,introducing a damage parameter considering the effects of closed pore gas.The loading effects of unsaturated loess under wide variations in saturation are described in a unified way,and the model performance is verified by corresponding stress and hydraulic path tests.The results indicated that the collapse response involves the initial void ratio of loess,and the coupled outwards motion of the loading-collapse(LC)yield surface under loading enhances its structural strength.Suction-enhanced yield stress requires a greater"tensile stress"to counteract its structural stability.The nucleation of bubbles at high saturation causes a decrease in yield stress.The loading effect exhibits a smaller collapse behavior when the influence of closed gas is considered,whereas the suction path does not cross the LC in the stress space under hydraulic action for the same parameters,which amplifies the influence of closed gas on loess deformation.
基金supported in part by the National Natural Science Foundation of China(NSFC)(Grant No.62001322)in part by the National Key Research and Development Program(Grant No.2020YFB2008800).
文摘In conventional piezoelectric micromachined ultrasonic transducers(PMUTs),the backside acoustic energy is often used inefficiently,resulting in up to half of the energy being wasted.Vacuum encapsulation can improve the energy utilization efficiency,but this technique is not compatible with state-of-the-art devices such as cantilever-based PMUTs.A closed back cavity provides an alternative method for effectively utilizing the backside acoustic energy.This paper investigates the effects of a closed back cavity on PMUT performance through theoretical analysis,simulations,and experimental verification.Increasing the cavity depth produces a periodic modulation of several key PMUT metrics,such as the relative frequency deviation and quality factor.The optimal cavity depth for PMUTs that ensures a robust resonant frequency and high quality factor is defined as a function of the acoustic wavelength.A closed back cavity also provides an effective method for continuously tuning the quality factor,and thus the bandwidth,of PMUTs.This work paves the way for air-coupled PMUTs with adjustable performance for various applications.
基金the Shanghai Municipal Education Commission-Gaofeng Clinical Medicine Grant(No.20172005)。
文摘Closed thoracic drainage can be performed using a steel-needle-guided chest tube to treat pleural effusion or pneumothorax in clinics.However,the puncture procedure during surgery is invisible,increasing the risk of surgical failure.Therefore,it is necessary to design a visualization system for closed thoracic drainage.Augmented reality(AR)technology can assist in visualizing the internal anatomical structure and determining the insertion point on the body surface.The structure of the currently used steel-needle-guided chest tube was modified by integrating it with an ultrafine diameter camera to provide real-time visualization of the puncture process.After simulation experiments,the overall registration error of the AR method was measured to be within(3.59±0.53)mm,indicating its potential for clinical application.The ultrafine diameter camera module and improved steel-needle-guided chest tube can timely reflect the position of the needle tip in the human body.A comparative experiment showed that video guidance could improve the safety of the puncture process compared to the traditional method.Finally,a qualitative evaluation of the usability of the system was conducted through a questionnaire.This system facilitates the visualization of closed thoracic drainage puncture procedure and pro-vides an implementation scheme to enhance the accuracy and safety of the operative step,which is conducive to reducing the learning curve and improving the proficiency of the doctors.
基金supported by King Abdullah University of Science and Technology(KAUST).
文摘A binary complete decision table with many-valued decisions is a table with n attributes and 2^(n) pairwise distinct rows filled with numbers from the set{0,1}.Each row of this table is labeled with a nonempty finite set of decisions.For a given row of the table,the task is to find a decision from the set of decisions attached to the row.Such tables are generalizations of Boolean functions.They can also be viewed as representations of various problems related to systems of decision rules.In this paper,we consider three types of classes of binary complete decision tables with many-valued decisions,closed with respect to removal of columns and changing of decisions.For tables from these classes,we study the relationships between the minimum weighted depth of deterministic,nondeterministic,and(for one type of classes)strongly nondeterministic decision trees and the total weight of attributes attached to columns.Note that nondeterministic decision trees and strongly nondeterministic decision trees for decision tables can be interpreted as a way of representing the two types of systems of decision rules for these tables.
基金supported by the National Key Research and Development Program of China(2022YFC2504303)Innovation Foundation of National Clinical Research Center for Orthopaedics,Sports Medicine&Rehabilitation(2021-NCRC-CXJJ-ZH-24)Medical Innovation and Transformation Incubation Project of Tongji Hospital(2022ZHFY10).
文摘Objective Close reduction and internal fixation have gained popularity for the treatment of pelvic fractures.However,the closed reduction of bilateral displaced posterior pelvic ring disruption is a great challenge even for the most experienced surgeon.In this study,we describe in detail a novel unlocking closed reduction technique(UCRT)frame that allows strong traction for bilateral posterior pelvic ring displacement and presents preliminary clinical outcomes.Methods We retrospectively reviewed 32 patients with bilateral displaced posterior pelvic ring disruptions(AO/OTA 61-C2 and C3)who were initially treated with this technique between July 2017 and July 2022.According to the AO/OTA clas-sification,there were 9 cases(28.12%)of 61-C2,and 23 cases(71.88%)of 61-C3.There were 11 males,21 females,with an average age of 38.1 years.The interval from injury to operation was 4-27 days,with a cut-off of 12.5 days(receiver operat-ing characteristic curve).Operative time,blood loss,and postoperative radiographic findings were recorded.The functional outcomes and complications were followed.Results A total of 30(93.8%)patients achieved successful closed reduction,whereas 2 required open reduction.The success-ful closed reduction rate was 95.5%(21/22)in patients whose injury-to-operation time was less than 12.5 days.The vertical displacement percent correction of the obviously displaced hemipelvis was 70.20%±16.79%on average.The average degree of pelvic deformity correction was 64.86%±17.71%.Thirty patients were followed up for at least 12 months(12-36 months),and no complications of nonunion or redisplacement were observed.The Matta-Tornetta scoring standard revealed that the excellent(25/30)and good(4/30)rate was 96.7%.The Majeed clinical efficacy score revealed that the overall excellent and good rate was 100%.One patient had INFIX-related infection,and 2 reported numbness in the lateral thigh.The numbness was improved after INFIX removal.Conclusions This study presents an updated technique for closed reduction using a UCRT frame for bilateral posterior pelvic ring disruption,which has been shown to be effective,as indicated by excellent surgical and functional outcomes.
文摘In this article,we are concerned with the C^(2)estimates for the k-convex solutions of a class of degenerate k-Hessian equations on closed Hermitian manifolds,whose function in the right-hand side is relevant to the unknown function and its gradient.We will get C^(0)estimate by promoting others′results,and get the“HMW estimate”of this equation such that the conditions of using blow-up analysis are satisfied,and the gradient estimate and second-order estimate will be obtained.Such an estimate will be helpful to study the existence for the solution of the equation.
基金a joint project of the University of Massachusetts and the Infrared Processing and Analysis Center/California Institute of Technology,funded by the National Aeronautics and Space Administration and the National Science Foundation。
文摘We present the essential stellar parameters of the close visual triple system HD 2893 using Al-Wardat's method for analyzing binary and multiple star systems in conjunction with Kurucz's model atmospheres.This method accurately computes the spectrophotometric stellar masses through a combined synthetic spectral energy distribution approach that compares the results with observed data.The vigorous approach uses spectroscopic,photometric,and dynamical analysis to yield precise results.The method implements Gaia DR3 measurements and other measurements like those of Hipparcos and 2MASS All-Sky Catalog as a guide for the best fit between the synthetic spectra and observed photometry.The analysis gives precise spectrophotometric stellar masses for the system being M_(Sph)^(A)=1.20±0.07M⊙,M_(Sph)^(B)=1.09±0.06M⊙,and M_(Sph)^(C)=0.46±0.01M⊙.It shows that the three components are main sequence stars with an estimated age of around 1.0 Gyr.When integrated with the dynamical analysis,a new dynamical parallax for the system is obtained,π_(dyn)=13.8528±0.20 mas.Additionally,the discussion covers the formation and evolution of the triple system.
文摘An analytic function f in the unit disk D ：= {z ∈ C ： ｜z｜ 〈 1}, standardly normalized, is called close-to-convex with respect to the Koebe function k（z） ：= z/（1-z）2, z ∈ D, if there exists δ ∈ （-π/2,π/2） such that Re {eiδ（1-z）2f′（z）} 〉 0, z ∈ D. For the class C（k） of all close-to-convex functions with respect to k, related to the class of functions convex in the positive direction of the imaginary axis, the Fekete-Szego problem is studied.
基金The National Natural Science Foundation of China(No50608017,50538020)
文摘Based on the theory of pattern recognition, the concept of closeness degree between fuzzy sets is brought into the condition assessment of long span bridges. Using the fuzzy analytic hierarchy process （FAHP）, a mathematical model of a multi-objective assessment of a long span suspension bridge is set up. An example is given to show the procedure in the synthetical condition assessment of the Runyang Suspension Bridge, which includes the hierarchical division, the definition of factor weights and fuzzy membership functions, and the calculation of closeness degrees, etc. The assessment combines both the data from the health monitoring system and the manual tests. The classification of evaluation items as well as the calculation of deterministic and nondeterministic items is presented. Compared with the traditional method of point rating, this method can better describe the discreteness of monitoring data and the fuzziness in the condition assessment.
文摘Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and Conclusion The criteria for singular points, closed orbits and hyperbolic equilibrium points of a second order autonomous Birkhoff system are given. Moreover the stability of equilibria, stable manifolds and unstable manifolds are obtained.
