We demonstrate that charge carrier diffusion lengths of two classes of perovskites, CH3NH3PbI3-xClx and CH3NH3PbI3, are both highly sensitive to film processing conditions and optimal processing procedures are critica...We demonstrate that charge carrier diffusion lengths of two classes of perovskites, CH3NH3PbI3-xClx and CH3NH3PbI3, are both highly sensitive to film processing conditions and optimal processing procedures are critical to preserving the long carrier diffusion lengths of the perovskite films. This understanding, together with the improved cathode interface using bilayer-structured electron transporting interlayers of [6,6]-phenyl-C61-butyric acid methyl ester （PCBM）/ZnO, leads to the successful fabrication of highly efficient, stable and reproducible planar heterojunction CH3NH3PbI3-xCl2 solar cells with impressive power-conversion efficiencies （PCEs） up to 15.9%. A 1-square-centimeter device yielding a PCE of 12.3% has been realized, demonstrating that this simple planar structure is promising for large-area devices.展开更多
Abstract--This paper conducts a survey on iterative learn- ing control （ILC） with incomplete information and associated control system design, which is a frontier of the ILC field. The incomplete information, includ...Abstract--This paper conducts a survey on iterative learn- ing control （ILC） with incomplete information and associated control system design, which is a frontier of the ILC field. The incomplete information, including passive and active types, can cause data loss or fragment due to various factors. Passive incomplete information refers to incomplete data and information caused by practical system limitations during data collection, storage, transmission, and processing, such as data dropouts, delays, disordering, and limited transmission bandwidth. Active incomplete information refers to incomplete data and information caused by man-made reduction of data quantity and quality on the premise that the given objective is satisfied, such as sampling and quantization. This survey emphasizes two aspects： the first one is how to guarantee good learning performance and tracking performance with passive incomplete data, and the second is how to balance the control performance index and data demand by active means. The promising research directions along this topic are also addressed, where data robustness is highly emphasized. This survey is expected to improve understanding of the restrictive relationship and trade-off between incomplete data and tracking performance, quantitatively, and promote further developments of ILC theory. Index Terms--Data dropout, data robustness, incomplete in- formation, iterative learning controi（ILC）, quantized control, sampled control, varying lengths.展开更多
In the United States, the costs of health care have become a major burden for the health care system. In order to address this problem, the hospitals of Syracuse, New York, developed programs to provide subacute and c...In the United States, the costs of health care have become a major burden for the health care system. In order to address this problem, the hospitals of Syracuse, New York, developed programs to provide subacute and complex care. The Subacute programs provided patient transportation services for dialysis and other types of care outside hospitals. They also developed programs for services such as intravenous therapy in nursing homes. The Complex Care Programs, such as intravenous therapy and mental health services, have provided alternatives to extended care in hospitals. During the past five years, utilization of these programs has varied, declining between 2019 and 2022, and then increasing between 2022 and 2024. The programs have avoided the need for 1530 - 2974 patient days in hospitals. The programs saved the Syracuse hospitals approximately $600 per inpatient day. This amounted to savings of $918,000 - $1,784,400 per year. These programs demonstrated how relatively small mechanisms can save large amounts of health care resources.展开更多
Quasi-2D Dion-Jacobson(DJ)tin halide perovskite has attracted much attention due to its elimination of Van der Waals gap and enhanced environmental stability.However,the bulky organic spacers usually form a natural qu...Quasi-2D Dion-Jacobson(DJ)tin halide perovskite has attracted much attention due to its elimination of Van der Waals gap and enhanced environmental stability.However,the bulky organic spacers usually form a natural quantum well structure,which brings a large quantum barrier and poor film quality,further limiting the carrier transport and device performance.Here,we designed three organic spacers with different chain lengths(ethylenediamine(EDA),1,3-propanediamine(PDA),and 1,4-butanediamine(BDA))to investigate the quantum barrier dependence.Theoretical and experimental characterizations indicate that EDA with short chain can reduce the lattice distortion and dielectric confinement effect,which is beneficial to the effective dissociation of excitons and the inhibition of trap-free non-radiative relaxation.In addition,EDA cation shows strong interaction with the inorganic octahedron,realizing large aggregates in precursor solution and high-quality films with improved structural stability.Furthermore,femtosecond transient absorption proves that EDA cations can also weaken the formation of small n-phases with large quantum barrier to achieve effective carrier transport between different nphases.Finally,the quasi-2D DJ(EDA)FA_(9)Sn_(10)I_(31)solar cells achieves a 7.07%power conversion efficiency with good environment stability.Therefore,this work sheds light on the regulation of the quantum barrier and carrier transport through the chain length of organic spacer for qua si-2D DJ lead-free perovskites.展开更多
In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and efficiency.In particular,an asym...In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and efficiency.In particular,an asymmetric trapezoidal flume with a length of 7 m and a width of 0.304 m is considered,with the bottom of the flume transversely inclined at an angle of m=0.296 and vertical lateral sides.The corresponding inflow Froude number is allowed to range in the interval(1.40<F1<6.11).The properties of this jump are compared to those of hydraulic jumps in channels with other types of cross-sections.A relationship for calculating hydraulic jump efficiency is proposed for the considered flume.For F1>5,the hydraulic jump is found to be more effective than that occurring in triangular and symmetric trapezoidal channels.Also,when■mes>8 and■>5,the hydraulic jump in the asymmetrical trapezoidal channel downstream of a parallelogram sluice gate is completely formed as opposed to the situation where a triangular sluice is considered.展开更多
The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(ID...The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.展开更多
Recent developments in health care have changed hospital utilization at the community level. This study provided examples of these changes in the metropolitan area of Syracuse, New York. The study demonstrated that pe...Recent developments in health care have changed hospital utilization at the community level. This study provided examples of these changes in the metropolitan area of Syracuse, New York. The study demonstrated that percent differences in discharges between the two time periods for both services changed little. For adult medicine, percent differences ranged between 16.5 and 18.0 percent while percent differences in adult surgery ranged from 23.25 to 24.93 percent. This information suggested that reductions in discharges during the five year period had stabilized. Most of these changes were associated with the movement of patients from inpatient to ambulatory care services. The largest numbers of these patients were associated with orthopedic surgery. They resulted from the movement of these patients who were at low severity of illness to ambulatory care settings. The study also identified increases in hospital lengths of stay for adult medicine and adult surgery between January-September 2019 and 2023 in the Syracuse hospitals. Adult medicine stays increased by 23.6 percent, from 4.84 to 5.98 days. Adult surgery stays increased by 25.5 percent, from 5.41 to 6.79 days.展开更多
This paper addresses an iterative learning control(ILC) design problem for discrete-time linear systems with randomly varying trial lengths. Due to the variation of the trial lengths, a stochastic matrix and an iterat...This paper addresses an iterative learning control(ILC) design problem for discrete-time linear systems with randomly varying trial lengths. Due to the variation of the trial lengths, a stochastic matrix and an iteration-average operator are introduced to present a unified expression of ILC scheme. By using the framework of lifted system, the learning convergence condition of ILC in mathematical expectation is derived without using λ-norm. It is shown that the requirement on classic ILC that all trial lengths must be identical is mitigated and the identical initialization condition can be also removed. In the end, two illustrative examples are presented to demonstrate the performance and the effectiveness of the proposed ILC scheme for both time-invariant and time-varying linear systems.展开更多
Cultures throughout the world are associating with the rivers.People depend upon the rivers and their tributaries for food,water,transport,and many other aspects of their daily lives.Unfortunately,human beings have no...Cultures throughout the world are associating with the rivers.People depend upon the rivers and their tributaries for food,water,transport,and many other aspects of their daily lives.Unfortunately,human beings have not calculated the accurate lengths for the great rivers even today.The lengths of the rivers are very different in popular textbooks,magazines,atlases and encyclopedias,etc.To accurately determine the lengths of the principal rivers of the world,the combination of satellite image analysis and field investigations to the source regions is proposed in this paper.The lengths of the Nile,Amazon,Yangtze,Mississippi,Yellow,Ob,Yenisey,Amur,Congo and Mekong,with lengths over or close to 5000 km,were calculated using the proposed method.The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable.展开更多
This work examines the fracture behavior of a functionally graded material （FGM） plate containing parallel surface cracks with alternating lengths subjected to a thermal shock. The thermal stress intensity factors ...This work examines the fracture behavior of a functionally graded material （FGM） plate containing parallel surface cracks with alternating lengths subjected to a thermal shock. The thermal stress intensity factors （TSIFs） at the tips of long and short cracks are calculated using a singular integral equation technique. The critical thermal shock △Tc that causes crack initiation is calculated using a stress intensity factor criterion. Numerical examples of TSIFs and △Tc for an Al2O3/Si3N4 FGM plate are presented to illustrate the effects of thermal property gradation, crack spacing and crack length ratio on the TSIFs and △Tc. It is found that for a given crack length ratio, the TSIFs at the tips of both long and short cracks can be reduced significantly and △Tc can be enhanced by introducing appropriate material gradation. The TSIFs also decrease dramatically with a decrease in crack spacing. The TSIF at the tips of short cracks may be higher than that for the long cracks under certain crack geometry conditions. Hence, the short cracks instead of long cracks may first start to grow under the thermal shock loading.展开更多
This case study described the structure and preliminary impact of a hospital program to improve efficiency by reducing long stays for adult medicine inpatients. The program focused resources on these patients, includi...This case study described the structure and preliminary impact of a hospital program to improve efficiency by reducing long stays for adult medicine inpatients. The program focused resources on these patients, including an experienced case management staff, effective relationships with long term care providers, and Subacute and Complex Care services. The program caused the total number of adult medicine patient days associated with these patients to decline by 1593, or 4780 on an annual basis.展开更多
Background: The management of infants (infs.) with esophageal atresia and tracheoesophageal fistula (EA ± TEF) is demanding and complex. The aim of this study was to evaluate early morbidity, the timing of surger...Background: The management of infants (infs.) with esophageal atresia and tracheoesophageal fistula (EA ± TEF) is demanding and complex. The aim of this study was to evaluate early morbidity, the timing of surgery, and the results of surgery. Patients and Method: We collected data of 30 consecutive infs. treated for EA ± TEF between 2006 and 2014. Results: The median gestational age was 38 weeks (12 preterm), and the median Birth Weight (BW) was 2660 g (4 infs. had a BW 1500 g). The median Apgar score at 10 minutes was 10 (range 7 - 10). The median umbilical artery pH (UapH) was 7.30. According to the Spitz classification, 19 infs. were group 1, 9 infs. were group 2, and 2 infs. were group 3. Surgical repair was performed in 29 cases (25 EA;4 isolated TEF). Once the infs. arrived at the pediatric surgery department, surgery was postponed overnight in 11 cases. The duration of postoperative (p.o.) mechanical ventilation was significantly shorter for operations performed on day 2 after delivery. Twenty-four infs. (83%) underwent surgery within 2 days after delivery, and 5 infs. had later surgery. Chest drains (p.o.) for pneumothorax were inserted in 6 infs. (21%), and gastrostomy was performed in 6 cases (21%). No re-thoracotomy was required. The median length of hospital stay was 17.5 days (6 to 120). The incidence of p.o. mortality was 1 in 29 (3%). Discussion: The majority of the infs. presented growth retardation (indicated by low birth weight) and a stable immediate postnatal course. The data from this study support the concept of early but not emergent surgery for the majority of infs. with EA ± TEF. However, a remarkable rate of perioperative morbidity must be taken into account. Conclusion: Surgery for EA ± TEF can be performed safely during the first postnatal days with exception of very unstable preterm infants.展开更多
Patients requiring Subacute and Complex Care services continue to challenge hospitals attempting to reduce inpatient stays and improve efficiency. In recent years, numbers of high severity of illness patients in hospi...Patients requiring Subacute and Complex Care services continue to challenge hospitals attempting to reduce inpatient stays and improve efficiency. In recent years, numbers of high severity of illness patients in hospitals have increased, adding to this challenge. Nurse care managers have a major responsibility for supporting the care of these patients. This study described the development of services for Subacute and Complex Care patients in the hospitals of Syracuse, New York. These hospitals used their own resources to develop programs including high cost medications, intravenous therapy, extensive wound care, and bariatric care in settings where they had not been available. In the absence of third party funding of another level of care, the hospitals provided program development funds for limited time periods in order to initiate these services. The Syracuse hospitals were able to phase out support for these programs after they were operational in the nursing homes for an extended period of time. The study data indicated that implementation of these programs limited the rate of increase of adult medicine stays and reduced adult surgery stays. The severity of illness for both major services increased in the Syracuse hospitals during this time. This process required acute and long term care providers who were interested in making the process work for the benefit of the patient populations involved, as well as for the needs of their own organizations.展开更多
This study described the evolution of programs to improve the efficiency of patient movement between hospitals and nursing homes in the metropolitan area of Syracuse, New York. These programs were needed in order to i...This study described the evolution of programs to improve the efficiency of patient movement between hospitals and nursing homes in the metropolitan area of Syracuse, New York. These programs were needed in order to improve coordination among providers in the absence of networks that included both acute and long term care providers. The mechanisms included the exchange of data and monitoring the movement of Difficult to Place patients from hospitals to nursing homes. Between 2006 and 2014, the annual number of Difficult to Place patients increased from 983 to 1836. During this period, annual hospital medical/surgical discharges increased by 7.5 percent, severity of illness increased by 13.7 percent, and the population aged 65 years and over increased by 9.8 percent. Most of the Difficult to Place patients were admitted by the four largest facilities in the community, which accounted for 60 percent of the nursing home beds. The initiatives also included Subacute and Complex Care Programs that provided financial incentives for admission of certain types of patients, such as intravenous therapy and extensive wound care. The programs described how these programs were implemented using minimal financial resources and without adding positions to the participating provider organizations.展开更多
Hospitals in the United States are being challenged to provide the capacity for adult medicine and surgery care. The study suggested that the hospitals of Syracuse, New York have generated additional inpatient capacit...Hospitals in the United States are being challenged to provide the capacity for adult medicine and surgery care. The study suggested that the hospitals of Syracuse, New York have generated additional inpatient capacity through a number of efforts. One program involved moving some low severity of illness inpatient procedures to ambulatory care. A different approach has also avoided inpatient utilization by diverting incoming ambulances to different providers. The third program evaluated in the study, length of stay reduction, was a different type of initiative. It has generated additional inpatient capacity by reducing the amount of inpatient care provided. In effect, it has increased inpatient capacity by addressing the efficiency of care. These programs illustrate the potential for improving hospital capacity at the community level. Each of them was developed by acute care providers using local services.展开更多
Well-aligned single-crystal nanowire arrays of CH3NH3PbIs have shown potentials in laser sources and photovoltaic applications.Here we developed a solution based epitaxial method to grow CH3NH3PbI3nanowire arrays.By c...Well-aligned single-crystal nanowire arrays of CH3NH3PbIs have shown potentials in laser sources and photovoltaic applications.Here we developed a solution based epitaxial method to grow CH3NH3PbI3nanowire arrays.By confining the precursor solution between a silicon wafer and ST-cut quartz,the evaporation rate of the solvent was slowed down which brings a more stable and controllable solution environment.Relying on the lattice match between CH3NH3PbI3 and ST-cut quartz,arrays of single-crystal nanowires of CH3NH3PbI3have been grown epitaxially.The densities and lengths of CH3NH3PbI3 nanowires can be tuned. The lengths of the resultant crystals range from several microns to over one millimeter.Such CH3NH3PbI3arrays with good alignment and crystallinity were then applied to fabricate photovoltaic devices with good performances.展开更多
A small cubic closed vessel with schlieren measurement technique combined with high-speed video camera were used to study limit flame properties under microgravity conditions at atmospheric pressure and room temperatu...A small cubic closed vessel with schlieren measurement technique combined with high-speed video camera were used to study limit flame properties under microgravity conditions at atmospheric pressure and room temperature.The rich flammability limit of C3H8/air was determined to be 9.2% C3H8.Stretched flame propagation speeds,stretched laminar burning velocities and unstretched laminar burning velocities near rich C3H8/air flammability limits were measured at different equivalence ratios.Outwardly propagating spherical flames were used to study the sensitivities of the flame propagation speeds and laminar burning velocities to flame stretch using Markstein lengths.Unstretched laminar burning velocity at rich flammability limit was determined to be 1.09cm/s.Lewis numbers were less than unity in rich C3H8/air and negative Markstein lengths were concluded.Absolute values of Markstein lengths were found to decrease linearly with equivalence ratios increase.展开更多
Length of stay outlier patients, who remain in hospitals for extended periods of time, is an important challenge to the improvement of health care efficiency. This study identified outlier patients and programs to add...Length of stay outlier patients, who remain in hospitals for extended periods of time, is an important challenge to the improvement of health care efficiency. This study identified outlier patients and programs to address them in the metropolitan area of Syracuse, New York. It demonstrated that, during 2013, outlier patients accounted for 2.4 percent of adult medicine discharges and an excess average daily census of 53.3 patients in the Syracuse hospitals. During 2013, outlier patients accounted for 4.3 percent of adult surgery discharges and an excess average daily census of 44.1 patients. In two studies, the Syracuse hospitals identified the need for multiple intravenous therapy, extensive wound care, and total parenteral nutrition in the community, as major causes of outlier stays in hospitals. Each of the hospitals has developed a program with a long term care facility to address these needs. Efforts to address outlier lengths of stay are also focusing on Potentially Preventable Complications in Syracuse. The mean length of stay for inpatients with post admissions complications was almost three times the stay for the medical/surgical population during 2013.展开更多
Bacterial flagellar filaments can undergo a polymorphic phase transition in both vitro and vivo environments. Each bacterial flagellar filament has 12 different helical forms which are macroscopically represented by d...Bacterial flagellar filaments can undergo a polymorphic phase transition in both vitro and vivo environments. Each bacterial flagellar filament has 12 different helical forms which are macroscopically represented by different pitch lengths and helix radii. For external mechanical force induced filament phase transitions, there is so far only one experiment performed by Hotani in 1982, who showed a very beautiful cyclic phase transition phenomenon in his experiment on isolated flagellar filaments. In the present paper, we give a detailed mechanical analysis on Hotani＇s experiments. Through theoretical computations, we obtained a phase transition rule based on the phase transition mechanism. The theoretical analysis provides a foundation facilitating the establishment of phase transition theory for bacterial flagellar filaments.展开更多
文摘We demonstrate that charge carrier diffusion lengths of two classes of perovskites, CH3NH3PbI3-xClx and CH3NH3PbI3, are both highly sensitive to film processing conditions and optimal processing procedures are critical to preserving the long carrier diffusion lengths of the perovskite films. This understanding, together with the improved cathode interface using bilayer-structured electron transporting interlayers of [6,6]-phenyl-C61-butyric acid methyl ester （PCBM）/ZnO, leads to the successful fabrication of highly efficient, stable and reproducible planar heterojunction CH3NH3PbI3-xCl2 solar cells with impressive power-conversion efficiencies （PCEs） up to 15.9%. A 1-square-centimeter device yielding a PCE of 12.3% has been realized, demonstrating that this simple planar structure is promising for large-area devices.
基金supported by the National Natural Science Foundation of China(61673045)Beijing Natural Science Foundation(4152040)
文摘Abstract--This paper conducts a survey on iterative learn- ing control （ILC） with incomplete information and associated control system design, which is a frontier of the ILC field. The incomplete information, including passive and active types, can cause data loss or fragment due to various factors. Passive incomplete information refers to incomplete data and information caused by practical system limitations during data collection, storage, transmission, and processing, such as data dropouts, delays, disordering, and limited transmission bandwidth. Active incomplete information refers to incomplete data and information caused by man-made reduction of data quantity and quality on the premise that the given objective is satisfied, such as sampling and quantization. This survey emphasizes two aspects： the first one is how to guarantee good learning performance and tracking performance with passive incomplete data, and the second is how to balance the control performance index and data demand by active means. The promising research directions along this topic are also addressed, where data robustness is highly emphasized. This survey is expected to improve understanding of the restrictive relationship and trade-off between incomplete data and tracking performance, quantitatively, and promote further developments of ILC theory. Index Terms--Data dropout, data robustness, incomplete in- formation, iterative learning controi（ILC）, quantized control, sampled control, varying lengths.
文摘In the United States, the costs of health care have become a major burden for the health care system. In order to address this problem, the hospitals of Syracuse, New York, developed programs to provide subacute and complex care. The Subacute programs provided patient transportation services for dialysis and other types of care outside hospitals. They also developed programs for services such as intravenous therapy in nursing homes. The Complex Care Programs, such as intravenous therapy and mental health services, have provided alternatives to extended care in hospitals. During the past five years, utilization of these programs has varied, declining between 2019 and 2022, and then increasing between 2022 and 2024. The programs have avoided the need for 1530 - 2974 patient days in hospitals. The programs saved the Syracuse hospitals approximately $600 per inpatient day. This amounted to savings of $918,000 - $1,784,400 per year. These programs demonstrated how relatively small mechanisms can save large amounts of health care resources.
基金financially supported by the National Key Research and Development Program of China(2022YFE0118400)the National Natural Science Foundation of China(51702038)+1 种基金the Science&Technology Department of Sichuan Province(2020YFG0061)the Recruitment Program for Young Professionals。
文摘Quasi-2D Dion-Jacobson(DJ)tin halide perovskite has attracted much attention due to its elimination of Van der Waals gap and enhanced environmental stability.However,the bulky organic spacers usually form a natural quantum well structure,which brings a large quantum barrier and poor film quality,further limiting the carrier transport and device performance.Here,we designed three organic spacers with different chain lengths(ethylenediamine(EDA),1,3-propanediamine(PDA),and 1,4-butanediamine(BDA))to investigate the quantum barrier dependence.Theoretical and experimental characterizations indicate that EDA with short chain can reduce the lattice distortion and dielectric confinement effect,which is beneficial to the effective dissociation of excitons and the inhibition of trap-free non-radiative relaxation.In addition,EDA cation shows strong interaction with the inorganic octahedron,realizing large aggregates in precursor solution and high-quality films with improved structural stability.Furthermore,femtosecond transient absorption proves that EDA cations can also weaken the formation of small n-phases with large quantum barrier to achieve effective carrier transport between different nphases.Finally,the quasi-2D DJ(EDA)FA_(9)Sn_(10)I_(31)solar cells achieves a 7.07%power conversion efficiency with good environment stability.Therefore,this work sheds light on the regulation of the quantum barrier and carrier transport through the chain length of organic spacer for qua si-2D DJ lead-free perovskites.
文摘In this study,the main properties of the hydraulic jump in an asymmetric trapezoidal flume are analyzed experimentally,including the so-called sequent depths,characteristic lengths,and efficiency.In particular,an asymmetric trapezoidal flume with a length of 7 m and a width of 0.304 m is considered,with the bottom of the flume transversely inclined at an angle of m=0.296 and vertical lateral sides.The corresponding inflow Froude number is allowed to range in the interval(1.40<F1<6.11).The properties of this jump are compared to those of hydraulic jumps in channels with other types of cross-sections.A relationship for calculating hydraulic jump efficiency is proposed for the considered flume.For F1>5,the hydraulic jump is found to be more effective than that occurring in triangular and symmetric trapezoidal channels.Also,when■mes>8 and■>5,the hydraulic jump in the asymmetrical trapezoidal channel downstream of a parallelogram sluice gate is completely formed as opposed to the situation where a triangular sluice is considered.
基金supported by Wuyi University Hong Kong and Macao Joint Research and Development Fund(GrantsNos.2021WGALH15,2019WGALH17,2019WGALH15)the National Natural Science Foundation of China-Guangdong Joint Fund(GrantsNo.2019A1515111052)+2 种基金the National Natural Science Foundation of China(Grant No.52202426)a grant from the Research Grants Council(RGC)of the Hong Kong Special Administrative Region(SAR),China(Grants No.15205723)a grant from the Hong Kong Polytechnic University(Grant No.P0045325).
文摘The safety and stability of high-speed maglev trains traveling on viaducts in crosswinds critically depend on their aerodynamic characteristics.Therefore,this paper uses an improved delayed detached eddy simulation(IDDES)method to investigate the aerodynamic features of high-speed maglev trains with different marshaling lengths under crosswinds.The effects of marshaling lengths(varying from 3-car to 8-car groups)on the train’s aerodynamic performance,surface pressure,and the flow field surrounding the train were investigated using the three-dimensional unsteady compressible Navier-Stokes(N-S)equations.The results showed that the marshaling lengths had minimal influence on the aerodynamic performance of the head and middle cars.Conversely,the marshaling lengths are negatively correlated with the time-average side force coefficient(CS)and time-average lift force coefficient(Cl)of the tail car.Compared to the tail car of the 3-car groups,the CS and Cl fell by 27.77%and 18.29%,respectively,for the tail car of the 8-car groups.It is essential to pay more attention to the operational safety of the head car,as it exhibits the highest time average CS.Additionally,the mean pressure difference between the two sides of the tail car body increased with the marshaling lengths,and the side force direction on the tail car was opposite to that of the head and middle cars.Furthermore,the turbulent kinetic energy of the wake structure on the windward side quickly decreased as marshaling lengths increased.
文摘Recent developments in health care have changed hospital utilization at the community level. This study provided examples of these changes in the metropolitan area of Syracuse, New York. The study demonstrated that percent differences in discharges between the two time periods for both services changed little. For adult medicine, percent differences ranged between 16.5 and 18.0 percent while percent differences in adult surgery ranged from 23.25 to 24.93 percent. This information suggested that reductions in discharges during the five year period had stabilized. Most of these changes were associated with the movement of patients from inpatient to ambulatory care services. The largest numbers of these patients were associated with orthopedic surgery. They resulted from the movement of these patients who were at low severity of illness to ambulatory care settings. The study also identified increases in hospital lengths of stay for adult medicine and adult surgery between January-September 2019 and 2023 in the Syracuse hospitals. Adult medicine stays increased by 23.6 percent, from 4.84 to 5.98 days. Adult surgery stays increased by 25.5 percent, from 5.41 to 6.79 days.
文摘This paper addresses an iterative learning control(ILC) design problem for discrete-time linear systems with randomly varying trial lengths. Due to the variation of the trial lengths, a stochastic matrix and an iteration-average operator are introduced to present a unified expression of ILC scheme. By using the framework of lifted system, the learning convergence condition of ILC in mathematical expectation is derived without using λ-norm. It is shown that the requirement on classic ILC that all trial lengths must be identical is mitigated and the identical initialization condition can be also removed. In the end, two illustrative examples are presented to demonstrate the performance and the effectiveness of the proposed ILC scheme for both time-invariant and time-varying linear systems.
基金supported by China High-Tech Research and Development Project(863 Project)the Innovation Project of Chinese Academy of Sciences,the Special Funds of Director General of Institute of Remote Sensing Applications,Chinese Academy of Sciences,the Funds of the State Key Laboratory of Remote Sensing Sciences of Chinathe Funds of the State Key Laboratory of Information Engineering in Surveying,Mapping and Remote Sensing of China and Earth&Space Awards of the Earth and Space Foundation.
文摘Cultures throughout the world are associating with the rivers.People depend upon the rivers and their tributaries for food,water,transport,and many other aspects of their daily lives.Unfortunately,human beings have not calculated the accurate lengths for the great rivers even today.The lengths of the rivers are very different in popular textbooks,magazines,atlases and encyclopedias,etc.To accurately determine the lengths of the principal rivers of the world,the combination of satellite image analysis and field investigations to the source regions is proposed in this paper.The lengths of the Nile,Amazon,Yangtze,Mississippi,Yellow,Ob,Yenisey,Amur,Congo and Mekong,with lengths over or close to 5000 km,were calculated using the proposed method.The results may represent the most reliable and accurate lengths of the principal rivers of the world that are currently achievable.
文摘This work examines the fracture behavior of a functionally graded material （FGM） plate containing parallel surface cracks with alternating lengths subjected to a thermal shock. The thermal stress intensity factors （TSIFs） at the tips of long and short cracks are calculated using a singular integral equation technique. The critical thermal shock △Tc that causes crack initiation is calculated using a stress intensity factor criterion. Numerical examples of TSIFs and △Tc for an Al2O3/Si3N4 FGM plate are presented to illustrate the effects of thermal property gradation, crack spacing and crack length ratio on the TSIFs and △Tc. It is found that for a given crack length ratio, the TSIFs at the tips of both long and short cracks can be reduced significantly and △Tc can be enhanced by introducing appropriate material gradation. The TSIFs also decrease dramatically with a decrease in crack spacing. The TSIF at the tips of short cracks may be higher than that for the long cracks under certain crack geometry conditions. Hence, the short cracks instead of long cracks may first start to grow under the thermal shock loading.
文摘This case study described the structure and preliminary impact of a hospital program to improve efficiency by reducing long stays for adult medicine inpatients. The program focused resources on these patients, including an experienced case management staff, effective relationships with long term care providers, and Subacute and Complex Care services. The program caused the total number of adult medicine patient days associated with these patients to decline by 1593, or 4780 on an annual basis.
文摘Background: The management of infants (infs.) with esophageal atresia and tracheoesophageal fistula (EA ± TEF) is demanding and complex. The aim of this study was to evaluate early morbidity, the timing of surgery, and the results of surgery. Patients and Method: We collected data of 30 consecutive infs. treated for EA ± TEF between 2006 and 2014. Results: The median gestational age was 38 weeks (12 preterm), and the median Birth Weight (BW) was 2660 g (4 infs. had a BW 1500 g). The median Apgar score at 10 minutes was 10 (range 7 - 10). The median umbilical artery pH (UapH) was 7.30. According to the Spitz classification, 19 infs. were group 1, 9 infs. were group 2, and 2 infs. were group 3. Surgical repair was performed in 29 cases (25 EA;4 isolated TEF). Once the infs. arrived at the pediatric surgery department, surgery was postponed overnight in 11 cases. The duration of postoperative (p.o.) mechanical ventilation was significantly shorter for operations performed on day 2 after delivery. Twenty-four infs. (83%) underwent surgery within 2 days after delivery, and 5 infs. had later surgery. Chest drains (p.o.) for pneumothorax were inserted in 6 infs. (21%), and gastrostomy was performed in 6 cases (21%). No re-thoracotomy was required. The median length of hospital stay was 17.5 days (6 to 120). The incidence of p.o. mortality was 1 in 29 (3%). Discussion: The majority of the infs. presented growth retardation (indicated by low birth weight) and a stable immediate postnatal course. The data from this study support the concept of early but not emergent surgery for the majority of infs. with EA ± TEF. However, a remarkable rate of perioperative morbidity must be taken into account. Conclusion: Surgery for EA ± TEF can be performed safely during the first postnatal days with exception of very unstable preterm infants.
文摘Patients requiring Subacute and Complex Care services continue to challenge hospitals attempting to reduce inpatient stays and improve efficiency. In recent years, numbers of high severity of illness patients in hospitals have increased, adding to this challenge. Nurse care managers have a major responsibility for supporting the care of these patients. This study described the development of services for Subacute and Complex Care patients in the hospitals of Syracuse, New York. These hospitals used their own resources to develop programs including high cost medications, intravenous therapy, extensive wound care, and bariatric care in settings where they had not been available. In the absence of third party funding of another level of care, the hospitals provided program development funds for limited time periods in order to initiate these services. The Syracuse hospitals were able to phase out support for these programs after they were operational in the nursing homes for an extended period of time. The study data indicated that implementation of these programs limited the rate of increase of adult medicine stays and reduced adult surgery stays. The severity of illness for both major services increased in the Syracuse hospitals during this time. This process required acute and long term care providers who were interested in making the process work for the benefit of the patient populations involved, as well as for the needs of their own organizations.
文摘This study described the evolution of programs to improve the efficiency of patient movement between hospitals and nursing homes in the metropolitan area of Syracuse, New York. These programs were needed in order to improve coordination among providers in the absence of networks that included both acute and long term care providers. The mechanisms included the exchange of data and monitoring the movement of Difficult to Place patients from hospitals to nursing homes. Between 2006 and 2014, the annual number of Difficult to Place patients increased from 983 to 1836. During this period, annual hospital medical/surgical discharges increased by 7.5 percent, severity of illness increased by 13.7 percent, and the population aged 65 years and over increased by 9.8 percent. Most of the Difficult to Place patients were admitted by the four largest facilities in the community, which accounted for 60 percent of the nursing home beds. The initiatives also included Subacute and Complex Care Programs that provided financial incentives for admission of certain types of patients, such as intravenous therapy and extensive wound care. The programs described how these programs were implemented using minimal financial resources and without adding positions to the participating provider organizations.
文摘Hospitals in the United States are being challenged to provide the capacity for adult medicine and surgery care. The study suggested that the hospitals of Syracuse, New York have generated additional inpatient capacity through a number of efforts. One program involved moving some low severity of illness inpatient procedures to ambulatory care. A different approach has also avoided inpatient utilization by diverting incoming ambulances to different providers. The third program evaluated in the study, length of stay reduction, was a different type of initiative. It has generated additional inpatient capacity by reducing the amount of inpatient care provided. In effect, it has increased inpatient capacity by addressing the efficiency of care. These programs illustrate the potential for improving hospital capacity at the community level. Each of them was developed by acute care providers using local services.
基金supported by the National Natural Science Foundation of China (21631002, U1632119, 21621061, and 91633301) Ministry of Science and Technology of the People’s Republic of China (2016YFA0201904)
文摘Well-aligned single-crystal nanowire arrays of CH3NH3PbIs have shown potentials in laser sources and photovoltaic applications.Here we developed a solution based epitaxial method to grow CH3NH3PbI3nanowire arrays.By confining the precursor solution between a silicon wafer and ST-cut quartz,the evaporation rate of the solvent was slowed down which brings a more stable and controllable solution environment.Relying on the lattice match between CH3NH3PbI3 and ST-cut quartz,arrays of single-crystal nanowires of CH3NH3PbI3have been grown epitaxially.The densities and lengths of CH3NH3PbI3 nanowires can be tuned. The lengths of the resultant crystals range from several microns to over one millimeter.Such CH3NH3PbI3arrays with good alignment and crystallinity were then applied to fabricate photovoltaic devices with good performances.
基金Supported by the Research Foundation of Beijing Institute of Technology(20070242004)
文摘A small cubic closed vessel with schlieren measurement technique combined with high-speed video camera were used to study limit flame properties under microgravity conditions at atmospheric pressure and room temperature.The rich flammability limit of C3H8/air was determined to be 9.2% C3H8.Stretched flame propagation speeds,stretched laminar burning velocities and unstretched laminar burning velocities near rich C3H8/air flammability limits were measured at different equivalence ratios.Outwardly propagating spherical flames were used to study the sensitivities of the flame propagation speeds and laminar burning velocities to flame stretch using Markstein lengths.Unstretched laminar burning velocity at rich flammability limit was determined to be 1.09cm/s.Lewis numbers were less than unity in rich C3H8/air and negative Markstein lengths were concluded.Absolute values of Markstein lengths were found to decrease linearly with equivalence ratios increase.
文摘Length of stay outlier patients, who remain in hospitals for extended periods of time, is an important challenge to the improvement of health care efficiency. This study identified outlier patients and programs to address them in the metropolitan area of Syracuse, New York. It demonstrated that, during 2013, outlier patients accounted for 2.4 percent of adult medicine discharges and an excess average daily census of 53.3 patients in the Syracuse hospitals. During 2013, outlier patients accounted for 4.3 percent of adult surgery discharges and an excess average daily census of 44.1 patients. In two studies, the Syracuse hospitals identified the need for multiple intravenous therapy, extensive wound care, and total parenteral nutrition in the community, as major causes of outlier stays in hospitals. Each of the hospitals has developed a program with a long term care facility to address these needs. Efforts to address outlier lengths of stay are also focusing on Potentially Preventable Complications in Syracuse. The mean length of stay for inpatients with post admissions complications was almost three times the stay for the medical/surgical population during 2013.
基金supported by the Hong Kong University of Science and Technology and the National Natural Science Foundation of China (10902013)
文摘Bacterial flagellar filaments can undergo a polymorphic phase transition in both vitro and vivo environments. Each bacterial flagellar filament has 12 different helical forms which are macroscopically represented by different pitch lengths and helix radii. For external mechanical force induced filament phase transitions, there is so far only one experiment performed by Hotani in 1982, who showed a very beautiful cyclic phase transition phenomenon in his experiment on isolated flagellar filaments. In the present paper, we give a detailed mechanical analysis on Hotani＇s experiments. Through theoretical computations, we obtained a phase transition rule based on the phase transition mechanism. The theoretical analysis provides a foundation facilitating the establishment of phase transition theory for bacterial flagellar filaments.
