This study investigates and explores the teaching of higher vocational English courses for non-English majors from the perspective of core competencies.First,it outlines the current research status of core competencie...This study investigates and explores the teaching of higher vocational English courses for non-English majors from the perspective of core competencies.First,it outlines the current research status of core competencies and analyzes the national-level requirements for English core competencies.Subsequently,based on professional training objectives and curriculum standards,a questionnaire on the core competencies of English courses has been designed to understand students’perceptions and experiences regarding the development of their competencies in areas such as workplace communication,cross-cultural exchange,language thinking enhancement,and autonomous learning improvement.The survey results showed that the majority of students had a positive attitude towards the effectiveness of English courses in cultivating the aforementioned core competencies.However,some students also suggest improvements,such as increasing practical opportunities and strengthening cultural exchange.Based on this,the study further explores how to integrate the cultivation of core competencies into classroom teaching,including the use of a combination of formative and summative assessments,the design of teaching content and activities related to the workplace and cross-cultural communication,and the guidance of students to actively explore and apply their knowledge,thereby enhancing their English language application abilities.This study has certain reference value for the optimization of the higher vocational English curriculum system and the reform of teaching methods.展开更多
In this paper,the failure caused by HRAM loads which were generated by high-speed projectile penetration,and protection technology of the fluid-filled structure were explored.A bubble was preset on the projectile traj...In this paper,the failure caused by HRAM loads which were generated by high-speed projectile penetration,and protection technology of the fluid-filled structure were explored.A bubble was preset on the projectile trajectory in a fluid-filled structure.Based on the reflection and transmission phenomena of pressure waves at the gas-liquid interface and the compressibility characteristics of gases,a numerical analysis was conducted on the influence of preset bubble on projectile penetration and structural failure characteristics.The results indicate that the secondary water-entry impact phenomenon occurs when a preset bubble exists on the projectile trajectory,leading to the secondary water entry impact loads.The rarefaction waves reflected on the surface of the preset bubble cause the attenuation ratio of the initial impact pressure peak to reach 68.8%and the total specific impulse attenuation ratio to reach 48.6%.Furthermore,the larger the bubble,the faster the projectile,and the more obvious the attenuation effect.Moreover,due to the compressibility of the bubble,the global deformation attenuation ratio of the front and rear walls can reach over 80%.However,the larger the bubble size,the faster the projectile velocity,the smaller the local deformation attenuation effect of the rear wall,and the more severe the failure at the perforation of the rear wall.展开更多
Understanding the photon number statistics of a quantum emitter(QE)interacting with complex photonic environments is fundamental to advances in quantum optics and nanophotonics.We introduce a general theoretical frame...Understanding the photon number statistics of a quantum emitter(QE)interacting with complex photonic environments is fundamental to advances in quantum optics and nanophotonics.We introduce a general theoretical framework for calculating the modal photon number density spectrum(MPNDS)in arbitrary dielectric structures with an embedded two-level QE.We validate our approach by investigating a system composed of a two-level QE and a photonic crystal(PhC)slab with an L3 cavity and a waveguide,finding that the MPNDS exhibits significant changes in both waveguide and background radiative channels as the interaction between the QE and modal field transitions from weak coupling to strong coupling.We observe that the number of photons guided along the waveguide shows a strong dependence on the QE’s transition frequency and transition dipole moment,but demonstrates robustness to the transition dipole moment when the transition frequency approaches the waveguide cutoff frequency.Our work allows for the determination and tailoring of light emission characteristics across diverse radiative channels in complex photonic environments.展开更多
BACKGROUND Acute upper gastrointestinal bleeding(AUGIB)is a common emergency critical illness that requires prompt assessment upon admission to prevent disease deterioration.As a resuscitation mode,the fast track for ...BACKGROUND Acute upper gastrointestinal bleeding(AUGIB)is a common emergency critical illness that requires prompt assessment upon admission to prevent disease deterioration.As a resuscitation mode,the fast track for emergency treatment increases the success rate and improves patient outcomes.However,misuse will consume resources.The Glasgow-Blatchford score(GBS)is considered to predict the clinical intervention needs for AUGIB patients,guiding diagnosis and treatment.Therefore,clinical research is needed to identify the recommended GBS thresholds that support effective use in AUGIB patients.AIM To validate the effectiveness of the GBS in establishing a fast track to reduce the time and cost of treatment for patients with AUGIB.METHODS A retrospective analysis was performed using the data of 124 cases of AUGIB patients with GBS≥6 treated at the University-Town Hospital of Chongqing Medical University from August 2020 to April 2023.Based on GBS risk stratification,patients were divided into moderate-risk(12>GBS≥6)and high-risk(GBS≥12)groups.Furthermore,depending on whether a fast track was established after the patients arrived in the emergency department,the patients were categorized into control and fast-track groups.The changes in various indicators,such as length of time in the emergency resuscitation room,door-to-endoscopy time,total blood transfusion volume,hospitalization duration,and hospitalization costs,were compared between the control and fast-track groups under each risk stratification level.RESULTS In the comparison of the aforementioned indicators,the moderate-risk fast-track group did not show any significant differences from the control group(P>0.05).However,in the high-risk fast-track group,the door-toendoscopy time,total blood transfusion volume,and hospitalization costs were significantly lower than those in the control group(P<0.05).CONCLUSION Establishing a fast track for emergency treatment based on GBS risk stratification has assessment value in reducing door-to-endoscopy time,decreasing total blood transfusion volume,and lowering hospitalization costs in patients with AUGIB.GBS≥12 is recommended as the threshold for implementing the fast track for emergency treatment,and its clinical promotion is advised.展开更多
The Casimir pressure plays an important role in the adhesion stability of nanofilms at submicro scales.In this work,the Casimir pressure of peptide films deposited on a layered substrate is investigated.Three types of...The Casimir pressure plays an important role in the adhesion stability of nanofilms at submicro scales.In this work,the Casimir pressure of peptide films deposited on a layered substrate is investigated.Three types of semi-infinite substrates,i.e.,silica,silicon and gold,are considered.The buffer layer between the peptide film and substrate consists of silicon or silica.The switching sign of the Casimir pressure can be controlled in a region ranging from about 130 nm to 1000 nm,depending on the thickness of the buffer layer and the substrate.The results suggest that the critical thickness of peptide films for Casimir equilibrium increases(or decreases)by increasing the thickness of the silicon(or silica)buffer film.The influences of wetting and electrolyte screening on the Casimir pressure are also investigated.Our finding provides a theoretical guide for the adhesion stability of peptide films in organic electronics.展开更多
The study aims to explore the damage characteristics and protection technologies of liquid-filled structures under high-speed projectile impact.A series of penetration impact experiments were conducted by focusing on ...The study aims to explore the damage characteristics and protection technologies of liquid-filled structures under high-speed projectile impact.A series of penetration impact experiments were conducted by focusing on different air layer configurations.By using high-speed camera and dynamic measurement systems,the effects of air layers on the projectile penetration,pressure wave propagation,cavitation evolution,and structural dynamic responses were analyzed.The results showed that the rarefaction wave reflected from the air-liquid interface significantly reduced the peak and specific impulse of the initial pressure wave,thereby diminishing the impact load on the structure.Additionally,the compressibility of air layers also attenuated the cavitation extrusion load.Both front and rear plates exhibited superimposed deformation modes,i.e.,local deformation or petal fracture with global deformation.Air layers effectively mitigated global deformation.However,when the air layer was positioned on the projectile's trajectory,it split the water-entry process and velocity attenuation of the projectile into two relatively independent phases.And the secondary water entry pressure wave caused more severe local deformation and petal fractures on the rear plate.展开更多
Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we inve...Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we investigate the enhancement of the negative friction experienced by nanospheres placed near a graphene substrate. We find that the magnitude of negative friction is related to the resonant coupling between the surface plasmon polaritons(SPPs) of the graphene and localized surface phonon polaritons(LSPh P) of nanospheres. We exam nanospheres consisted of several different materials, including SiO_(2), Si C, Zn Se, Na Cl, ln Sb. Our results suggest that the LSPh P of Na Cl nanospheres match effectively with the amplified SPPs of graphene sheets. The negative friction for Na Cl nanospheres can be enhanced about one-to-two orders of magnitude compared to that of silica(SiO_(2)) nanospheres. At the resonant peak of negative friction, the required quasi-Fermi energy of graphene is lower for Na Cl nanospheres. Our finds hold great prospects for the mechanical manipulations of nanoscale particles.展开更多
We investigated the ionization and dissociation processes of ammonia clusters ranging from dimer to pentamer induced by 800-nm femtosecond laser fields.Time-of-flight(TOF)mass spectra of the ammonia clusters were reco...We investigated the ionization and dissociation processes of ammonia clusters ranging from dimer to pentamer induced by 800-nm femtosecond laser fields.Time-of-flight(TOF)mass spectra of the ammonia clusters were recorded over a range of laser intensities from 2.1×10^(12)W/cm^(2) to 5.6×10^(12)W/cm^(2).The protonated ion signals dominate the spectra,which is consistent with the stability of the geometric structures.The ionization and dissociation channels of ammonia clusters are discussed.The competition and switching among observed dissociation channels are revealed by analyzing the variations in the relative ionic yields of specific protonated and unprotonated clusters under different laser intensities.These results indicate that the ionization of the neutral multiple-ammonia units,produced through the dissociation of cluster ions,may start to contribute,as well as the additional processes to consume protonated ions and/or produce unprotonated ions induced by the femtosecond laser fields when the laser intensity is above^4×10^(12)W/cm^(2).These findings provide deeper insights into the ionization and dissociation dynamics in multi-photon ionization experiments involving ammonia clusters.展开更多
Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present,...Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer＇s disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines （interleukin-2, interferon-y） and hippocampal microglia-related cyto- kines （interleukin-113, tumor necrosis factor-a） correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer＇s disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer＇s disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer＇s disease.展开更多
This paper deals with a cold standby repairman who can do extra work in idle time. The repairable system with two identical units and one authors are devoted to studying the unique existence and exponential stability ...This paper deals with a cold standby repairman who can do extra work in idle time. The repairable system with two identical units and one authors are devoted to studying the unique existence and exponential stability of the system solution. C0-semigroup theory is used to prove the existence of a unique nonnegative time-dependent solution of the system. Then by using the theory of resolvent positive operator, the authors derive that dynamic solution of the system exponentially converges to its steady-state one which is the eigenfunction corresponding to eigenvalue 0 of the system operator. Some reliability indices of the system are discussed with a different method from traditional one. The authors also make a profit analysis to determine the optimal service time outside the system to maximize the system profit.展开更多
Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels （behavior, sublethal, lethal）. In this study, the toxicity of chlorpyrif...Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels （behavior, sublethal, lethal）. In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints （acute, chronic, behavioral）. Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects at concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.展开更多
Based on the differential constitutive relationship of linearviscoelastic material, a solid-liquid coupling vibration equation forviscoelastic pipe conveying fluid is derived by the D'Alembert'sprinciple. The ...Based on the differential constitutive relationship of linearviscoelastic material, a solid-liquid coupling vibration equation forviscoelastic pipe conveying fluid is derived by the D'Alembert'sprinciple. The critical flow velocities and natural frequencies ofthe cantilever pipe conveying fluid with the Kelvin model (flutterinstability) are calculated with the modified finite differencemethod in the form of the recurrence for- mula. The curves betweenthe complex frequencies of the first, second and third mode and flowvelocity of the pipe are plotted. On the basis of the numericalcalculation results, the dynamic behaviors and stability of the pipeare discussed. It should be pointed out that the delay time ofviscoelastic material with the Kelvin model has a remarkable effecton the dynamic characteristics and stability behaviors of thecantilevered pipe conveying fluid, which is a gyroscopicnon-conservative system.展开更多
In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formul...In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formulated in a simple and consistent manner. Selective maintenance problem under economic dependence(EDSMP) is presented based on a series–parallel system in this paper. A case study shows that the system reliability is promoted to a certain extent, which can validate the validity of the EDSMP model. The influence of the ratio of set-up cost on system performance is mainly discussed under different economic dependences. Several existing improvements of classical exhaust algorithm are further modified to solve a large sized EDSMP rapidly. Experimental results illustrate that these improvements can reduce CPU time significantly.Furthermore the contribution of each improvement is defined here, and then their contributions are compared thoroughly.展开更多
The problem of optimal guaranteed cost control for discrete-time singular large-scale systems with a quadratic cost function is considered in this paper. The system under discussion is subject to norm bounded time-inv...The problem of optimal guaranteed cost control for discrete-time singular large-scale systems with a quadratic cost function is considered in this paper. The system under discussion is subject to norm bounded time-invariant parameter uncertainty in all the matrices of model. The problem we address is to design a state feedback controller such that the closed-loop system not only is robustly stable but also guarantees an adequate level of performance for all admissible uncertainties. A sufficient condition for the existence of guaranteed cost controllers is presented in terms of linear matrix inequalities (LMIs), and a desired state feedback controller is obtained via convex optimization. An illustrative example is given to demonstrate the effectiveness of the proposed approach.展开更多
Two new phenylethanoid glycosides,named scroside H（1）,scroside I（2）,and a new secoiridoid glycoside,named picrogentioside I（3）,have been isolated from the underground parts of Picrorhiza scrophulariiflora.Their ...Two new phenylethanoid glycosides,named scroside H（1）,scroside I（2）,and a new secoiridoid glycoside,named picrogentioside I（3）,have been isolated from the underground parts of Picrorhiza scrophulariiflora.Their structures were elucidated on the basis of spectroscopic evidence.展开更多
OBJECTIVE: To investigate the clinical differentiation of spleen-deficiency pattern(SDP), a group of symptoms and signs defined in terms of Traditional Chinese Medicine for its clinical practice.METHODS: Peripheral ve...OBJECTIVE: To investigate the clinical differentiation of spleen-deficiency pattern(SDP), a group of symptoms and signs defined in terms of Traditional Chinese Medicine for its clinical practice.METHODS: Peripheral venous blood(> 3 m L) was collected from each of six type 2 diabetes mellitus(T2DM)-SDP patients and six healthy volunteers. After the isolation of peripheral white blood cells(PWBCs), total RNA was extracted, and quality control was performed on all RNA samples. Microarray experiments were conducted using the Agilent human whole genome gene chip, and genes demonstrating differential expression were screened. Bioinformatics analysis was conducted on these genes using several online databases.RESULTS: We screened a total of 175 differentially expressed genes(DEGs), of which 111(63%) were down-regulated and 64(37%) were up-regulated in T2DM-SDP patients compared with healthy controls. Among the 175 genes, 158 had biological function annotations: 46(29%) were directly related to an individual's immune regulation or response, 25(16%) were associated with substance and energy metabolism of PWBCs which could also indirectly influence immunity, and the remaining87(55%) were involved in a variety of PWBC biological processes that might eventually influence the immune function. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the DEGs were predominantly enriched in seven immune-related pathways. Hierarchical cluster analysis identified gene expression patterns that were distinguishable between the two study groups.CONCLUSION: Our results suggest that T2DM-SDP patients experience significant hypoimmunity and/or immune dysfunctions, and possess a specific gene expression profile. These findings offer new insights into SDP and the clinical pattern differentiation of T2DM-SDP.展开更多
For the accurate description of aerodynamic characteristics for aircraft,a wavelet neural network (WNN) aerodynamic modeling method from flight data,based on improved particle swarm optimization (PSO) algorithm with i...For the accurate description of aerodynamic characteristics for aircraft,a wavelet neural network (WNN) aerodynamic modeling method from flight data,based on improved particle swarm optimization (PSO) algorithm with information sharing strategy and velocity disturbance operator,is proposed.In improved PSO algorithm,an information sharing strategy is used to avoid the premature convergence as much as possible;the velocity disturbance operator is adopted to jump out of this position once falling into the premature convergence.Simulations on lateral and longitudinal aerodynamic modeling for ATTAS (advanced technologies testing aircraft system) indicate that the proposed method can achieve the accuracy improvement of an order of magnitude compared with SPSO-WNN,and can converge to a satisfactory precision by only 60 120 iterations in contrast to SPSO-WNN with 6 times precocities in 200 times repetitive experiments using Morlet and Mexican hat wavelet functions.Furthermore,it is proved that the proposed method is feasible and effective for aerodynamic modeling from flight data.展开更多
OBJECTIVE: To study the effects of Zhiweifangbian (ZWFB) capsule on lactic dehydrogenase (LDH), succinic dehydrogenase (SDH) and ATPase activities in gastric mucosa of chronic atrophic gastritis (CAG) rats with Qi def...OBJECTIVE: To study the effects of Zhiweifangbian (ZWFB) capsule on lactic dehydrogenase (LDH), succinic dehydrogenase (SDH) and ATPase activities in gastric mucosa of chronic atrophic gastritis (CAG) rats with Qi deficiency and blood stasis syndrome. METHODS: Totally 90 rats were randomly divided into 2 groups: normal group (n=10) and modelgroup (n=80). The CAG rat model of Qi deficiency and blood stasis type was induced by synthetic methods. After modeling for 12 weeks and the successful CAG model was determined, the CAG model rats were divided by random number table into model group (MG), ZWFB high-dose group (ZWFBH), ZWFB middle-dose group (ZWFBM), ZWFB low-dose group (ZWFBL) and Weimeisu group (WM), 9 rats in each group. The rats in the normal and model groups were intragastrically administrated with distilled water, 10 mL/kg every day; the ZWFB high-dose group with ZWFB, 0.6 g/ kg -1 · d -1 ; the ZWFB middle-dose group with ZWFB, 0.3 g/kg -1 · d -1 ; the ZWFB low-dose group with ZWFB, 0.15 g/kg -1 · d -1 , and the WM group with suspension of WM , 0.25 g/kg -1 · d -1 . The treatment was given for 90 consecutive days. Then general survival states were observed and the activities of LDH, SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase in gastric mucosa tissue were detected. RESULTS: Compared with the normal group, activity of LDH in the gastric mucosa (P<0.05) and activities of SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase significantly decreased in the normal group (P<0.05). Compared with the model group the activity of LDH decreased and activities of SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase significantly increased in the high dose ZWFB group (P<0.05). CONCLUSION: ZWFB capsule can promote energy metabolism and ATPase activity in the gastric mucosa cell, so as to protect the function of the gastric mucosa cell.展开更多
Numerical simulation based on phase field method was performed to describe the solidification of silicon. The effect of anisotropy, undercooling and coupling parameter on dendrite growth shape was investigated. It is ...Numerical simulation based on phase field method was performed to describe the solidification of silicon. The effect of anisotropy, undercooling and coupling parameter on dendrite growth shape was investigated. It is indicated that the entire facet dendrite shapes are obtained by using regularized phase field model. Steady state tip velocity of dendrite drives to a fixed value when γ≤0.13. With further increasing the anisotropy value, steady state tip velocity decreases and the size is smaller. With the increase in the undercooling and coupling parameter, crystal grows from facet to facet dendrite. In addition, with increasing coupling parameter, the facet part of facet dendrite decreases gradually, which is in good agreement with Wulff theory.展开更多
基金The General Subject of the 2023 Vocational College Foreign Language Education Reform Special Project of the Foreign Language Education Committee,China Vocational and Technical Education Association“Research and Practice on the Reform of the Evaluation System for Public English Teaching in Higher Vocational Education from the Perspective of Core Competencies”(WYW2023A29)。
文摘This study investigates and explores the teaching of higher vocational English courses for non-English majors from the perspective of core competencies.First,it outlines the current research status of core competencies and analyzes the national-level requirements for English core competencies.Subsequently,based on professional training objectives and curriculum standards,a questionnaire on the core competencies of English courses has been designed to understand students’perceptions and experiences regarding the development of their competencies in areas such as workplace communication,cross-cultural exchange,language thinking enhancement,and autonomous learning improvement.The survey results showed that the majority of students had a positive attitude towards the effectiveness of English courses in cultivating the aforementioned core competencies.However,some students also suggest improvements,such as increasing practical opportunities and strengthening cultural exchange.Based on this,the study further explores how to integrate the cultivation of core competencies into classroom teaching,including the use of a combination of formative and summative assessments,the design of teaching content and activities related to the workplace and cross-cultural communication,and the guidance of students to actively explore and apply their knowledge,thereby enhancing their English language application abilities.This study has certain reference value for the optimization of the higher vocational English curriculum system and the reform of teaching methods.
文摘In this paper,the failure caused by HRAM loads which were generated by high-speed projectile penetration,and protection technology of the fluid-filled structure were explored.A bubble was preset on the projectile trajectory in a fluid-filled structure.Based on the reflection and transmission phenomena of pressure waves at the gas-liquid interface and the compressibility characteristics of gases,a numerical analysis was conducted on the influence of preset bubble on projectile penetration and structural failure characteristics.The results indicate that the secondary water-entry impact phenomenon occurs when a preset bubble exists on the projectile trajectory,leading to the secondary water entry impact loads.The rarefaction waves reflected on the surface of the preset bubble cause the attenuation ratio of the initial impact pressure peak to reach 68.8%and the total specific impulse attenuation ratio to reach 48.6%.Furthermore,the larger the bubble,the faster the projectile,and the more obvious the attenuation effect.Moreover,due to the compressibility of the bubble,the global deformation attenuation ratio of the front and rear walls can reach over 80%.However,the larger the bubble size,the faster the projectile velocity,the smaller the local deformation attenuation effect of the rear wall,and the more severe the failure at the perforation of the rear wall.
基金Project supported by the Basic and Applied Basic Research Project,Guangzhou Basic Research Plan(Grant No.202201011444).
文摘Understanding the photon number statistics of a quantum emitter(QE)interacting with complex photonic environments is fundamental to advances in quantum optics and nanophotonics.We introduce a general theoretical framework for calculating the modal photon number density spectrum(MPNDS)in arbitrary dielectric structures with an embedded two-level QE.We validate our approach by investigating a system composed of a two-level QE and a photonic crystal(PhC)slab with an L3 cavity and a waveguide,finding that the MPNDS exhibits significant changes in both waveguide and background radiative channels as the interaction between the QE and modal field transitions from weak coupling to strong coupling.We observe that the number of photons guided along the waveguide shows a strong dependence on the QE’s transition frequency and transition dipole moment,but demonstrates robustness to the transition dipole moment when the transition frequency approaches the waveguide cutoff frequency.Our work allows for the determination and tailoring of light emission characteristics across diverse radiative channels in complex photonic environments.
基金Supported by the Key Discipline of Pathology at Chongqing Medical and Pharmaceutical College,No.ygz2021303.
文摘BACKGROUND Acute upper gastrointestinal bleeding(AUGIB)is a common emergency critical illness that requires prompt assessment upon admission to prevent disease deterioration.As a resuscitation mode,the fast track for emergency treatment increases the success rate and improves patient outcomes.However,misuse will consume resources.The Glasgow-Blatchford score(GBS)is considered to predict the clinical intervention needs for AUGIB patients,guiding diagnosis and treatment.Therefore,clinical research is needed to identify the recommended GBS thresholds that support effective use in AUGIB patients.AIM To validate the effectiveness of the GBS in establishing a fast track to reduce the time and cost of treatment for patients with AUGIB.METHODS A retrospective analysis was performed using the data of 124 cases of AUGIB patients with GBS≥6 treated at the University-Town Hospital of Chongqing Medical University from August 2020 to April 2023.Based on GBS risk stratification,patients were divided into moderate-risk(12>GBS≥6)and high-risk(GBS≥12)groups.Furthermore,depending on whether a fast track was established after the patients arrived in the emergency department,the patients were categorized into control and fast-track groups.The changes in various indicators,such as length of time in the emergency resuscitation room,door-to-endoscopy time,total blood transfusion volume,hospitalization duration,and hospitalization costs,were compared between the control and fast-track groups under each risk stratification level.RESULTS In the comparison of the aforementioned indicators,the moderate-risk fast-track group did not show any significant differences from the control group(P>0.05).However,in the high-risk fast-track group,the door-toendoscopy time,total blood transfusion volume,and hospitalization costs were significantly lower than those in the control group(P<0.05).CONCLUSION Establishing a fast track for emergency treatment based on GBS risk stratification has assessment value in reducing door-to-endoscopy time,decreasing total blood transfusion volume,and lowering hospitalization costs in patients with AUGIB.GBS≥12 is recommended as the threshold for implementing the fast track for emergency treatment,and its clinical promotion is advised.
基金supported by the National Natural Science Foundation of China(Grant No.11804288)the Natural Science Foundation of Henan(Grant No.232300420120)。
文摘The Casimir pressure plays an important role in the adhesion stability of nanofilms at submicro scales.In this work,the Casimir pressure of peptide films deposited on a layered substrate is investigated.Three types of semi-infinite substrates,i.e.,silica,silicon and gold,are considered.The buffer layer between the peptide film and substrate consists of silicon or silica.The switching sign of the Casimir pressure can be controlled in a region ranging from about 130 nm to 1000 nm,depending on the thickness of the buffer layer and the substrate.The results suggest that the critical thickness of peptide films for Casimir equilibrium increases(or decreases)by increasing the thickness of the silicon(or silica)buffer film.The influences of wetting and electrolyte screening on the Casimir pressure are also investigated.Our finding provides a theoretical guide for the adhesion stability of peptide films in organic electronics.
基金the financial support provided by National Natural Science Foundation of China(Grant Nos.52271338,52371342 and 51979277).
文摘The study aims to explore the damage characteristics and protection technologies of liquid-filled structures under high-speed projectile impact.A series of penetration impact experiments were conducted by focusing on different air layer configurations.By using high-speed camera and dynamic measurement systems,the effects of air layers on the projectile penetration,pressure wave propagation,cavitation evolution,and structural dynamic responses were analyzed.The results showed that the rarefaction wave reflected from the air-liquid interface significantly reduced the peak and specific impulse of the initial pressure wave,thereby diminishing the impact load on the structure.Additionally,the compressibility of air layers also attenuated the cavitation extrusion load.Both front and rear plates exhibited superimposed deformation modes,i.e.,local deformation or petal fracture with global deformation.Air layers effectively mitigated global deformation.However,when the air layer was positioned on the projectile's trajectory,it split the water-entry process and velocity attenuation of the projectile into two relatively independent phases.And the secondary water entry pressure wave caused more severe local deformation and petal fractures on the rear plate.
基金Project supported by the National Natural Science Foundation of China (Grant No. 11804288)the Key Scientific Research Project of Higher Education Institutions in Henan Province, China (Grant No. 20231205164502999)。
文摘Negative friction refers to a frictional force that acts in the same direction as the motion of an object, which has been predicted in terahertz(THz) gain systems [Phys. Rev. B 108 045406(2023)]. In this work, we investigate the enhancement of the negative friction experienced by nanospheres placed near a graphene substrate. We find that the magnitude of negative friction is related to the resonant coupling between the surface plasmon polaritons(SPPs) of the graphene and localized surface phonon polaritons(LSPh P) of nanospheres. We exam nanospheres consisted of several different materials, including SiO_(2), Si C, Zn Se, Na Cl, ln Sb. Our results suggest that the LSPh P of Na Cl nanospheres match effectively with the amplified SPPs of graphene sheets. The negative friction for Na Cl nanospheres can be enhanced about one-to-two orders of magnitude compared to that of silica(SiO_(2)) nanospheres. At the resonant peak of negative friction, the required quasi-Fermi energy of graphene is lower for Na Cl nanospheres. Our finds hold great prospects for the mechanical manipulations of nanoscale particles.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.92261201,12134005,12334011)。
文摘We investigated the ionization and dissociation processes of ammonia clusters ranging from dimer to pentamer induced by 800-nm femtosecond laser fields.Time-of-flight(TOF)mass spectra of the ammonia clusters were recorded over a range of laser intensities from 2.1×10^(12)W/cm^(2) to 5.6×10^(12)W/cm^(2).The protonated ion signals dominate the spectra,which is consistent with the stability of the geometric structures.The ionization and dissociation channels of ammonia clusters are discussed.The competition and switching among observed dissociation channels are revealed by analyzing the variations in the relative ionic yields of specific protonated and unprotonated clusters under different laser intensities.These results indicate that the ionization of the neutral multiple-ammonia units,produced through the dissociation of cluster ions,may start to contribute,as well as the additional processes to consume protonated ions and/or produce unprotonated ions induced by the femtosecond laser fields when the laser intensity is above^4×10^(12)W/cm^(2).These findings provide deeper insights into the ionization and dissociation dynamics in multi-photon ionization experiments involving ammonia clusters.
基金supported by the National Natural Science Foundation of China,No.30840073the Medical Science Foundation of Guangdong Province,No.A2012298
文摘Alzheimer＇s disease is closely associated with disorders of neurogenesis in the brain, and growing evidence supports the involvement of immunological mechanisms in the development of the disease. However, at present, the role of T cells in neuronal regeneration in the brain is unknown. We injected amyloid-beta 1-42 peptide into the hippocampus of six BALB/c wild-type mice and six BALB/c-nude mice with T-cell immunodeficiency to establish an animal model of Alzhei- mer＇s disease. A further six mice of each genotype were injected with same volume of normal saline. Immunohistochemistry revealed that the number of regenerated neural progenitor cells in the hippocampus of BALB/c wild-type mice was significantly higher than that in BALB/c-nude mice. Quantitative fluorescence PCR assay showed that the expression levels of peripheral T cell-associated cytokines （interleukin-2, interferon-y） and hippocampal microglia-related cyto- kines （interleukin-113, tumor necrosis factor-a） correlated with the number of regenerated neural progenitor cells in the hippocampus. These results indicate that T cells promote hippocampal neurogenesis in Alzheimer＇s disease and T-cell immunodeficiency restricts neuronal regeneration in the hippocampus. The mechanism underlying the promotion of neuronal regeneration by T cells is mediated by an increased expression of peripheral T cells and central microglial cytokines in Alzheimer＇s disease mice. Our findings provide an experimental basis for understanding the role of T cells in Alzheimer＇s disease.
基金supported by the National Natural Science Foundation of China under Grant No.11201007
文摘This paper deals with a cold standby repairman who can do extra work in idle time. The repairable system with two identical units and one authors are devoted to studying the unique existence and exponential stability of the system solution. C0-semigroup theory is used to prove the existence of a unique nonnegative time-dependent solution of the system. Then by using the theory of resolvent positive operator, the authors derive that dynamic solution of the system exponentially converges to its steady-state one which is the eigenfunction corresponding to eigenvalue 0 of the system operator. Some reliability indices of the system are discussed with a different method from traditional one. The authors also make a profit analysis to determine the optimal service time outside the system to maximize the system profit.
基金Preject supported by the New Century Excellent Talents in Chinese Uni-versity (No. NCET-04-0914)the National Natural Science Foundationof China (No. 30640022)Yunnan Natural Sciences Foundations (No.2002C0001Z, 2005C0004Q).
文摘Earthworm toxicity tests are useful tools for terrestrial risk assessment but require a hierarchy of test designs that differ in effect levels （behavior, sublethal, lethal）. In this study, the toxicity of chlorpyrifos contaminated soil on earthworms was assessed. In addition to the acute and chronic tests, an avoidance response test was applied. Earthworms were exposed to sublethal and lethal concentration of chlorpyrifos, and evaluated for acute toxicity, growth, fecundity and avoidance response after a certain exposure period. The test methods covered all important ecological relevant endpoints （acute, chronic, behavioral）. Concentration of 78.91 mg/kg, chlorpyrifos caused significant toxic effects in all test methods, but at lower test concentrations, only significant chronic toxic effects could be observed. In present study, chlorpyrifos had adverse effect on growth and fecundity in earthworm exposed to 5 mg/kg chlorpyrifos after eight weeks. The avoidance response test, however, showed significant repellent effects at concentration of 40 mg/kg chlorpyrifos. For chlorpyrifos, concentration affecting avoidance response was far greater than growth and fecundity, it seemed likely that earthworms were not able to escape from pesticide-contaminated soil into the clean soil in field and hence were exposed continuously to elevated concentrations of pesticides.
文摘Based on the differential constitutive relationship of linearviscoelastic material, a solid-liquid coupling vibration equation forviscoelastic pipe conveying fluid is derived by the D'Alembert'sprinciple. The critical flow velocities and natural frequencies ofthe cantilever pipe conveying fluid with the Kelvin model (flutterinstability) are calculated with the modified finite differencemethod in the form of the recurrence for- mula. The curves betweenthe complex frequencies of the first, second and third mode and flowvelocity of the pipe are plotted. On the basis of the numericalcalculation results, the dynamic behaviors and stability of the pipeare discussed. It should be pointed out that the delay time ofviscoelastic material with the Kelvin model has a remarkable effecton the dynamic characteristics and stability behaviors of thecantilevered pipe conveying fluid, which is a gyroscopicnon-conservative system.
基金supported by the National Science Foundation of China (Grant No. 61305083)
文摘In view of the high complexity of the objective world, an economic dependence between subsystems(paired and unpaired) is proposed, and then the maintenance cost and time under different economic dependences are formulated in a simple and consistent manner. Selective maintenance problem under economic dependence(EDSMP) is presented based on a series–parallel system in this paper. A case study shows that the system reliability is promoted to a certain extent, which can validate the validity of the EDSMP model. The influence of the ratio of set-up cost on system performance is mainly discussed under different economic dependences. Several existing improvements of classical exhaust algorithm are further modified to solve a large sized EDSMP rapidly. Experimental results illustrate that these improvements can reduce CPU time significantly.Furthermore the contribution of each improvement is defined here, and then their contributions are compared thoroughly.
文摘The problem of optimal guaranteed cost control for discrete-time singular large-scale systems with a quadratic cost function is considered in this paper. The system under discussion is subject to norm bounded time-invariant parameter uncertainty in all the matrices of model. The problem we address is to design a state feedback controller such that the closed-loop system not only is robustly stable but also guarantees an adequate level of performance for all admissible uncertainties. A sufficient condition for the existence of guaranteed cost controllers is presented in terms of linear matrix inequalities (LMIs), and a desired state feedback controller is obtained via convex optimization. An illustrative example is given to demonstrate the effectiveness of the proposed approach.
基金supported by National Natural Science Foundation of China(No.30800835)National Key Project of Scientific and Technical Supporting Programs funded by Ministry of Science & Technology of China(No. 2006BAD31B05)
文摘Two new phenylethanoid glycosides,named scroside H（1）,scroside I（2）,and a new secoiridoid glycoside,named picrogentioside I（3）,have been isolated from the underground parts of Picrorhiza scrophulariiflora.Their structures were elucidated on the basis of spectroscopic evidence.
基金Supported by the Administration of Traditional Chinese Medicine of Guangdong Province of China(Study on the Relevance Between the Pi-Deficiency Syndrome and Gene Differential Expression Profile of Immunity and Metabolism in Type 2 Diabetic MellitusNo.20123001)+8 种基金Special Funds from the Central Finance of China in Support of the Development of Local Colleges and Universities[Collaborative Innovation Platform for the Prevention and Treatment of Significant and Refractory Pi-Wei DiseasesEducational Finance Grant No.338(2013)]the National Natural Science Foundation of China(the Mechanism Study of Salivary Alpha Amylase Activity Change in Pi-Deficiency Syndrome Patients Based on the AMY1 Copy Number VariationN-Glycosylated Protein Level and β-Adrenergic Receptor ActivationNo.81102703)the Science and Technology Planning Project of Guangdong Province of China (miRNA as Material Basis for the New Hypothesis"Pi-Metabolism Relevance"and Study on the Molecular Mechanisms of Treating Metabolic Disorders Through PiNo.2013A032500005)
文摘OBJECTIVE: To investigate the clinical differentiation of spleen-deficiency pattern(SDP), a group of symptoms and signs defined in terms of Traditional Chinese Medicine for its clinical practice.METHODS: Peripheral venous blood(> 3 m L) was collected from each of six type 2 diabetes mellitus(T2DM)-SDP patients and six healthy volunteers. After the isolation of peripheral white blood cells(PWBCs), total RNA was extracted, and quality control was performed on all RNA samples. Microarray experiments were conducted using the Agilent human whole genome gene chip, and genes demonstrating differential expression were screened. Bioinformatics analysis was conducted on these genes using several online databases.RESULTS: We screened a total of 175 differentially expressed genes(DEGs), of which 111(63%) were down-regulated and 64(37%) were up-regulated in T2DM-SDP patients compared with healthy controls. Among the 175 genes, 158 had biological function annotations: 46(29%) were directly related to an individual's immune regulation or response, 25(16%) were associated with substance and energy metabolism of PWBCs which could also indirectly influence immunity, and the remaining87(55%) were involved in a variety of PWBC biological processes that might eventually influence the immune function. Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed that the DEGs were predominantly enriched in seven immune-related pathways. Hierarchical cluster analysis identified gene expression patterns that were distinguishable between the two study groups.CONCLUSION: Our results suggest that T2DM-SDP patients experience significant hypoimmunity and/or immune dysfunctions, and possess a specific gene expression profile. These findings offer new insights into SDP and the clinical pattern differentiation of T2DM-SDP.
文摘For the accurate description of aerodynamic characteristics for aircraft,a wavelet neural network (WNN) aerodynamic modeling method from flight data,based on improved particle swarm optimization (PSO) algorithm with information sharing strategy and velocity disturbance operator,is proposed.In improved PSO algorithm,an information sharing strategy is used to avoid the premature convergence as much as possible;the velocity disturbance operator is adopted to jump out of this position once falling into the premature convergence.Simulations on lateral and longitudinal aerodynamic modeling for ATTAS (advanced technologies testing aircraft system) indicate that the proposed method can achieve the accuracy improvement of an order of magnitude compared with SPSO-WNN,and can converge to a satisfactory precision by only 60 120 iterations in contrast to SPSO-WNN with 6 times precocities in 200 times repetitive experiments using Morlet and Mexican hat wavelet functions.Furthermore,it is proved that the proposed method is feasible and effective for aerodynamic modeling from flight data.
基金Supported by National Natural Science Fund (No.81260519)Science and Technique Plan of the Administration of Traditional Chinese Medicine of Gansu Province(No.07-GZK-07)Experimental Plan for Young and Middleaged Teacher of Gansu College of Traditional Chinese Medicine(No. 05ZQ-03/09ZQ-09)
文摘OBJECTIVE: To study the effects of Zhiweifangbian (ZWFB) capsule on lactic dehydrogenase (LDH), succinic dehydrogenase (SDH) and ATPase activities in gastric mucosa of chronic atrophic gastritis (CAG) rats with Qi deficiency and blood stasis syndrome. METHODS: Totally 90 rats were randomly divided into 2 groups: normal group (n=10) and modelgroup (n=80). The CAG rat model of Qi deficiency and blood stasis type was induced by synthetic methods. After modeling for 12 weeks and the successful CAG model was determined, the CAG model rats were divided by random number table into model group (MG), ZWFB high-dose group (ZWFBH), ZWFB middle-dose group (ZWFBM), ZWFB low-dose group (ZWFBL) and Weimeisu group (WM), 9 rats in each group. The rats in the normal and model groups were intragastrically administrated with distilled water, 10 mL/kg every day; the ZWFB high-dose group with ZWFB, 0.6 g/ kg -1 · d -1 ; the ZWFB middle-dose group with ZWFB, 0.3 g/kg -1 · d -1 ; the ZWFB low-dose group with ZWFB, 0.15 g/kg -1 · d -1 , and the WM group with suspension of WM , 0.25 g/kg -1 · d -1 . The treatment was given for 90 consecutive days. Then general survival states were observed and the activities of LDH, SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase in gastric mucosa tissue were detected. RESULTS: Compared with the normal group, activity of LDH in the gastric mucosa (P<0.05) and activities of SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase significantly decreased in the normal group (P<0.05). Compared with the model group the activity of LDH decreased and activities of SDH, Na + -K + -ATPase and Ca 2+ -Mg 2+ -ATPase significantly increased in the high dose ZWFB group (P<0.05). CONCLUSION: ZWFB capsule can promote energy metabolism and ATPase activity in the gastric mucosa cell, so as to protect the function of the gastric mucosa cell.
基金Projects(50331040 60171034) supported by the National Natural Science Foundation of China
文摘Numerical simulation based on phase field method was performed to describe the solidification of silicon. The effect of anisotropy, undercooling and coupling parameter on dendrite growth shape was investigated. It is indicated that the entire facet dendrite shapes are obtained by using regularized phase field model. Steady state tip velocity of dendrite drives to a fixed value when γ≤0.13. With further increasing the anisotropy value, steady state tip velocity decreases and the size is smaller. With the increase in the undercooling and coupling parameter, crystal grows from facet to facet dendrite. In addition, with increasing coupling parameter, the facet part of facet dendrite decreases gradually, which is in good agreement with Wulff theory.
