Plasma jet has extensive application potentials in various fields, which normally operates in a diffuse mode when helium is used as the working gas. However, when less expensive argon is used, the plasma jet often ope...Plasma jet has extensive application potentials in various fields, which normally operates in a diffuse mode when helium is used as the working gas. However, when less expensive argon is used, the plasma jet often operates in a filamentary mode. Compared to the filamentary mode, the diffuse mode is more desirable for applications. Hence, many efforts have been exerted to accomplish the diffuse mode of the argon plasma jet. In this paper, a novel single-needle argon plasma jet is developed to obtain the diffuse mode. It is found that the plasma jet operates in the filamentary mode when the distance from the needle tip to the central line of the argon stream(d) is short. It transits to the diffuse mode with increasing d. For the diffuse mode, there is always one discharge pulse per voltage cycle, which initiates at the rising edge of the positive voltage. For comparison, the number of discharge pulse increases with an increase in the peak voltage for the filamentary mode. Fast photography reveals that the plasma plume in the filamentary mode results from a guided positive streamer,which propagates in the argon stream. However, the plume in the diffuse mode originates from a branched streamer, which propagates in the interfacial layer between the argon stream and the surrounding air. By optical emission spectroscopy,plasma parameters are investigated for the two discharge modes, which show a similar trend with increasing d. The diffuse mode has lower electron temperature, electron density, vibrational temperature, and gas temperature compared to the filamentary mode.展开更多
The key plasma parameters under different discharge modes, such as heavy-particle and electron temperatures, electron number density, and nonequilibrium volume of plasmas, play important roles in various applications ...The key plasma parameters under different discharge modes, such as heavy-particle and electron temperatures, electron number density, and nonequilibrium volume of plasmas, play important roles in various applications of gas discharge plasmas. In this study, a self-consistent two-dimensional nonequilibrium fluid model coupled with an external circuit model is established to reveal the mechanisms related to the discharge modes, including the normal glow, abnormal glow,arc, and glow-to-arc transition modes, with an atmospheric-pressure direct-current(DC) argon discharge as a model plasma system. The modeling results show that, under different discharge modes, the most significant difference between the preceding four discharge modes lies in the current and energy transfer processes on the cathode side. On one hand, the current to the cathode surface is mainly delivered by the ions coming from the plasma column under the glow discharge mode due to the low temperature of the solid cathode, whereas the thermionic and secondary electrons emitted from the hot cathode surface play a very important role under the arc mode with a higher cathode surface temperature and higher ion flux toward the cathode. On the other hand, the energy transfer channel on the cathode side changes from mainly heating the solid cathode under the glow mode to simultaneously heating both the solid cathode and plasma column under the arc mode with an increase in the discharge current. Consequently, the power density in the cathode sheath(P_c) was used as a key parameter for judging different discharge modes, and the range of(0.28–1.2) × 10^(12) W m^(-3) was determined as a critical window of P_c corresponding to the glow-to-arc-mode transition for the atmospheric-pressure DC argon discharge, which was also verified by comparison with the experimental results in this study and the data in the previous literature.展开更多
In response to the recommendation by the American Assembly of Collegiate Schools of Business(AACSB,2002),which urged business schools to embark on interdisciplinary programs to facilitate boundary-spanning teaching an...In response to the recommendation by the American Assembly of Collegiate Schools of Business(AACSB,2002),which urged business schools to embark on interdisciplinary programs to facilitate boundary-spanning teaching and learning,many colleges have conducted one form of curriculum integration or the other.Many of these team-taught course integrations,however,concentrate on core business courses without reaching out to related courses in other disciplines.Moreover,due to some factors,the informational contents of management disclosures in annual reports and audit unqualified opinions may not align with the future viability of an enterprise.Using a“going concern concept”,this paper demonstrates how the addition of economics in business school curriculum integration could produce well-rounded business graduates.Economics concepts could unambiguously support the tests that cast doubts on firms’ability to continue operations.展开更多
BACKGROUND Patients with colorectal cancer may need postoperative nursing to improve prognosis,and conventional nursing is not effective.Clinical research is needed to explore nursing methods that can more effectively...BACKGROUND Patients with colorectal cancer may need postoperative nursing to improve prognosis,and conventional nursing is not effective.Clinical research is needed to explore nursing methods that can more effectively improve postoperative conditions on colorectal cancer patients undergoing colostomy.AIM To explore the effect of internet multiple linkage mode-based extended care combined with in-hospital comfort care on colorectal cancer patients undergoing colostomy.METHODS Data from 187 patients with colostomy treated in our hospital from May 2019 to March 2022 were collected and divided into three groups,A(n=62),B(n=62)and C(n=63),according to different intervention methods.Group A received internet multiple linkage mode-based extended care combined with in-hospital comfort care.Group B received internet multiple linkage mode-based extended care.Group C received usual care intervention.Complications were compared among the three groups.The stoma self-efficacy scale,Hamilton Anxiety Scale,RESULTS The complication rate of group A,B and C(16.13%,20.97%and 60.32%,respectively)was significantly different(all P<0.05).The incidence of complications in groups A and B was lower than that in group C,and there was no significant difference between groups A and B(P>0.05).After intervention,the scores of ostomy care,social contact,diet choice,confidence in maintaining vitality,confidence in self-care of ostomy,confidence in sexual life,confidence in sexual satisfaction and confidence in physical labor in the three groups were all higher than before intervention,and the scores of groups A and B were higher than those of group C,with statistical significance(P<0.05).The Hamilton Anxiety Scale and Hamilton Depression Scale scores of the three groups after intervention were lower than those before intervention.The scores of groups A and B were lower than those of group C,and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).There was a statist-ically significant difference in cancer-induced fatigue among the three groups(P<0.05).After intervention,the scores of physical health,psychological health,social health and mental health of the three groups were lower than before the intervention.The scores of group A and B were lower than that of group C;and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).CONCLUSION Internet multiple linkage mode-based extended care combined with in-hospital comfort care can effectively improve self-efficacy,bad mood,cancer-related fatigue and life quality of colorectal cancer patients undergoing colostomy.展开更多
In this work,we investigated the discharge characteristics and heating mechanisms of argon helicon plasma in different wave coupled modes with and without blue core.Spatially resolved spectroscopy and emission intensi...In this work,we investigated the discharge characteristics and heating mechanisms of argon helicon plasma in different wave coupled modes with and without blue core.Spatially resolved spectroscopy and emission intensity of argon atom and ion lines were measured via local optical emission spectroscopy,and electron density was measured experimentally by an RFcompensated Langmuir probe.The relation between the emission intensity and the electron density was obtained and the wavenumbers of helicon and’Trivelpiece-Gould’(TG)waves were calculated by solving the dispersion relation in wave modes.The results show that at least two distinct wave coupled modes appear in argon helicon plasma at increasing RF power,i.e.blue core(or BC)mode with a significant bright core of blue lights and a normal wave(NW)mode without blue core.The emission intensity of atom line 750.5 nm(lArⅠ750.5nm)is related to the electron density and tends to be saturated in wave coupled modes due to the neutral depletion,while the intensity of ion line 480.6 nm(IArⅡ480.6nm)is a function of the electron density and temperature,and increases dramatically as the RF power is increased.Theoretical analysis shows that TG waves are strongly damped at the plasma edge in NW and/or BC modes,while helicon waves are the dominant mechanism of power deposition or central heating of electrons in both modes.The formation of BC column mainly depends on the enhanced central electron heating by helicon waves rather than TG waves since the excitation of TG waves would be suppressed in this special anti-resonance region.展开更多
Ptychographic extreme ultraviolet(EUV)diffractive imaging has emerged as a promising candidate for the next generationmetrology solutions in the semiconductor industry,as it can image wafer samples in reflection geome...Ptychographic extreme ultraviolet(EUV)diffractive imaging has emerged as a promising candidate for the next generationmetrology solutions in the semiconductor industry,as it can image wafer samples in reflection geometry at the nanoscale.This technique has surged attention recently,owing to the significant progress in high-harmonic generation(HHG)EUV sources and advancements in both hardware and software for computation.In this study,a novel algorithm is introduced and tested,which enables wavelength-multiplexed reconstruction that enhances the measurement throughput and introduces data diversity,allowing the accurate characterisation of sample structures.To tackle the inherent instabilities of the HHG source,a modal approach was adopted,which represents the crossdensity function of the illumination by a series of mutually incoherent and independent spatial modes.The proposed algorithm was implemented on a mainstream machine learning platform,which leverages automatic differentiation to manage the drastic growth in model complexity and expedites the computation using GPU acceleration.By optimising over 2oo million parameters,we demonstrate the algorithm's capacity to accommodate experimental uncertainties and achieve a resolution approaching the diffraction limit in reflection geometry.The reconstruction of wafer samples with 20-nm high patterned gold structures on a silicon substrate highlights our ability to handle complex physical interrelations involving a multitude of parameters.These results establish ptychography as an efficient and accurate metrology tool.展开更多
The ability to manipulate microlaser is highly desirable towards high-performance optoelectronic devices.Here we demonstrate feasible mode manipulation of Fabry-Perot type microlasers of a perovskite nanowire via inco...The ability to manipulate microlaser is highly desirable towards high-performance optoelectronic devices.Here we demonstrate feasible mode manipulation of Fabry-Perot type microlasers of a perovskite nanowire via incorporation of single gold nanoparticles.The influences of resonant wavelength,quality factor and emission directions are successively investigated using a two-dimensional finite-difference time-domain method.It is found that blueshift of resonant wavelength could be achieved together with either promoted or degraded quality factor of the microlaser via single Au NPs with varied sizes.Unidirectional emission could also be realized which is favorable for on-chip integration.Our results provide useful reference for feasible manipulation of light-matter interactions and mode selection.展开更多
Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).I...Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).In this work,to protect the sensor nodes with low RE,we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold.Besides,we employ an Unmanned Aerial Vehicle(UAV)to collect the stored data from the heterogeneous WSN.We aim to jointly optimize the cluster head selection,energy threshold and sensor nodes’working mode to minimize the weighted sum of energy con-sumption from the WSN and UAV,subject to the data collection rate constraint.To this end,we propose an efficient search method to search for an optimal energy threshold,and develop a penalty-based successive convex approximation algorithm to select the cluster heads.Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure.Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.展开更多
BACKGROUND Acute cerebral infarction is a severe type of ischemic stroke that can be divided into anterior circulation cerebral infarction and posterior circulation cerebral infarction(PCCI).PCCI affects the structure...BACKGROUND Acute cerebral infarction is a severe type of ischemic stroke that can be divided into anterior circulation cerebral infarction and posterior circulation cerebral infarction(PCCI).PCCI affects the structure of the posterior circulation brain,because posterior part of the brain,which has more complex anatomical structures and more prone to posterior circulation vascular variation.Therefore,improving the prognosis of PCCI patients is necessary.AIM To explore the effect of medical care linkage-continuous management mode(MCLMM)on endovascular interventional therapy(EIT)for PCCI.METHODS Sixty-nine patients with PCCI who received EIT and conventional nursing intervention were selected as the control group,and 78 patients with PCCI who received EIT and MCLMM intervention were selected as the observation group.The incidence of postoperative complications,compliance and disease selfmanagement behavior after six months of intervention,modified Rankin scale(mRS)and Barthel index(BI)scores in the acute phase and after one year of intervention,and recurrence within one year were compared between the two groups.RESULTS The total incidence rate of postoperative complications in the observation group(7.69%)was lower than that in the control group(18.84%)(P<0.05).The scores for medical compliance behavior(regular medication,appropriate diet,and rehabilitation cooperation rates)and disease self-management behavior(self-will,disease knowledge,and self-care ability)in the observation group were higher than those in the control group(P<0.05).After one year of intervention,in the observation group,the mRS score was significantly lower,and the BI score was significantly higher than those in the control group(P<0.05).The recurrence rate within one year in the observation group(3.85%)was significantly lower than that in the control group(13.04%)(P<0.05).CONCLUSION MCLMM can reduce the incidence of complications after EIT for PCCI,improve patient compliance behavior and disease self-management ability,and promote the recovery of neurological function.展开更多
The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external disturbances.This paper proposes a barrier function-base...The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external disturbances.This paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for NWMRs.Compared with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances bounds.Another advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier function.The benefit is that the overestimation of control gain can be eliminated,resulting in chattering reduction.Moreover,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the actuator.The stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.展开更多
Offshore engineering construction projects are large and complex,having the characteristics of multiple execution modes andmultiple resource constraints.Their complex internal scheduling processes can be regarded as r...Offshore engineering construction projects are large and complex,having the characteristics of multiple execution modes andmultiple resource constraints.Their complex internal scheduling processes can be regarded as resourceconstrained project scheduling problems(RCPSPs).To solve RCPSP problems in offshore engineering construction more rapidly,a hybrid genetic algorithmwas established.To solve the defects of genetic algorithms,which easily fall into the local optimal solution,a local search operation was added to a genetic algorithm to defend the offspring after crossover/mutation.Then,an elitist strategy and adaptive operators were adopted to protect the generated optimal solutions,reduce the computation time and avoid premature convergence.A calibrated function method was used to cater to the roulette rules,and appropriate rules for encoding,decoding and crossover/mutation were designed.Finally,a simple network was designed and validated using the case study of a real offshore project.The performance of the genetic algorithmand a simulated annealing algorithmwas compared to validate the feasibility and effectiveness of the approach.展开更多
基金Project supported by the National Natural Science Foundation of China (Grant Nos.51977057,11875121,and 11805013)the Natural Science Foundation of Hebei Province,China (Grant Nos.A2020201025 and A2022201036)+2 种基金the Funds for Distinguished Young Scientists of Hebei Province,China (Grant No.A2012201045)the Natural Science Interdisciplinary Research Program of Hebei University (Grant No.DXK202011)the Postgraduate’s Innovation Fund Project of Hebei University (Grant No.HBU2022bs004)。
文摘Plasma jet has extensive application potentials in various fields, which normally operates in a diffuse mode when helium is used as the working gas. However, when less expensive argon is used, the plasma jet often operates in a filamentary mode. Compared to the filamentary mode, the diffuse mode is more desirable for applications. Hence, many efforts have been exerted to accomplish the diffuse mode of the argon plasma jet. In this paper, a novel single-needle argon plasma jet is developed to obtain the diffuse mode. It is found that the plasma jet operates in the filamentary mode when the distance from the needle tip to the central line of the argon stream(d) is short. It transits to the diffuse mode with increasing d. For the diffuse mode, there is always one discharge pulse per voltage cycle, which initiates at the rising edge of the positive voltage. For comparison, the number of discharge pulse increases with an increase in the peak voltage for the filamentary mode. Fast photography reveals that the plasma plume in the filamentary mode results from a guided positive streamer,which propagates in the argon stream. However, the plume in the diffuse mode originates from a branched streamer, which propagates in the interfacial layer between the argon stream and the surrounding air. By optical emission spectroscopy,plasma parameters are investigated for the two discharge modes, which show a similar trend with increasing d. The diffuse mode has lower electron temperature, electron density, vibrational temperature, and gas temperature compared to the filamentary mode.
基金supported by National Natural Science Foundation of China (No. 12075132)。
文摘The key plasma parameters under different discharge modes, such as heavy-particle and electron temperatures, electron number density, and nonequilibrium volume of plasmas, play important roles in various applications of gas discharge plasmas. In this study, a self-consistent two-dimensional nonequilibrium fluid model coupled with an external circuit model is established to reveal the mechanisms related to the discharge modes, including the normal glow, abnormal glow,arc, and glow-to-arc transition modes, with an atmospheric-pressure direct-current(DC) argon discharge as a model plasma system. The modeling results show that, under different discharge modes, the most significant difference between the preceding four discharge modes lies in the current and energy transfer processes on the cathode side. On one hand, the current to the cathode surface is mainly delivered by the ions coming from the plasma column under the glow discharge mode due to the low temperature of the solid cathode, whereas the thermionic and secondary electrons emitted from the hot cathode surface play a very important role under the arc mode with a higher cathode surface temperature and higher ion flux toward the cathode. On the other hand, the energy transfer channel on the cathode side changes from mainly heating the solid cathode under the glow mode to simultaneously heating both the solid cathode and plasma column under the arc mode with an increase in the discharge current. Consequently, the power density in the cathode sheath(P_c) was used as a key parameter for judging different discharge modes, and the range of(0.28–1.2) × 10^(12) W m^(-3) was determined as a critical window of P_c corresponding to the glow-to-arc-mode transition for the atmospheric-pressure DC argon discharge, which was also verified by comparison with the experimental results in this study and the data in the previous literature.
文摘In response to the recommendation by the American Assembly of Collegiate Schools of Business(AACSB,2002),which urged business schools to embark on interdisciplinary programs to facilitate boundary-spanning teaching and learning,many colleges have conducted one form of curriculum integration or the other.Many of these team-taught course integrations,however,concentrate on core business courses without reaching out to related courses in other disciplines.Moreover,due to some factors,the informational contents of management disclosures in annual reports and audit unqualified opinions may not align with the future viability of an enterprise.Using a“going concern concept”,this paper demonstrates how the addition of economics in business school curriculum integration could produce well-rounded business graduates.Economics concepts could unambiguously support the tests that cast doubts on firms’ability to continue operations.
基金Supported by Clinical Teaching Base of Jiangsu Medical Vocational College,No.20219141.
文摘BACKGROUND Patients with colorectal cancer may need postoperative nursing to improve prognosis,and conventional nursing is not effective.Clinical research is needed to explore nursing methods that can more effectively improve postoperative conditions on colorectal cancer patients undergoing colostomy.AIM To explore the effect of internet multiple linkage mode-based extended care combined with in-hospital comfort care on colorectal cancer patients undergoing colostomy.METHODS Data from 187 patients with colostomy treated in our hospital from May 2019 to March 2022 were collected and divided into three groups,A(n=62),B(n=62)and C(n=63),according to different intervention methods.Group A received internet multiple linkage mode-based extended care combined with in-hospital comfort care.Group B received internet multiple linkage mode-based extended care.Group C received usual care intervention.Complications were compared among the three groups.The stoma self-efficacy scale,Hamilton Anxiety Scale,RESULTS The complication rate of group A,B and C(16.13%,20.97%and 60.32%,respectively)was significantly different(all P<0.05).The incidence of complications in groups A and B was lower than that in group C,and there was no significant difference between groups A and B(P>0.05).After intervention,the scores of ostomy care,social contact,diet choice,confidence in maintaining vitality,confidence in self-care of ostomy,confidence in sexual life,confidence in sexual satisfaction and confidence in physical labor in the three groups were all higher than before intervention,and the scores of groups A and B were higher than those of group C,with statistical significance(P<0.05).The Hamilton Anxiety Scale and Hamilton Depression Scale scores of the three groups after intervention were lower than those before intervention.The scores of groups A and B were lower than those of group C,and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).There was a statist-ically significant difference in cancer-induced fatigue among the three groups(P<0.05).After intervention,the scores of physical health,psychological health,social health and mental health of the three groups were lower than before the intervention.The scores of group A and B were lower than that of group C;and the score of group A was lower than that of group B,all with statistical significance(all P<0.05).CONCLUSION Internet multiple linkage mode-based extended care combined with in-hospital comfort care can effectively improve self-efficacy,bad mood,cancer-related fatigue and life quality of colorectal cancer patients undergoing colostomy.
基金National Natural Science Foundation of China(No.11975047)。
文摘In this work,we investigated the discharge characteristics and heating mechanisms of argon helicon plasma in different wave coupled modes with and without blue core.Spatially resolved spectroscopy and emission intensity of argon atom and ion lines were measured via local optical emission spectroscopy,and electron density was measured experimentally by an RFcompensated Langmuir probe.The relation between the emission intensity and the electron density was obtained and the wavenumbers of helicon and’Trivelpiece-Gould’(TG)waves were calculated by solving the dispersion relation in wave modes.The results show that at least two distinct wave coupled modes appear in argon helicon plasma at increasing RF power,i.e.blue core(or BC)mode with a significant bright core of blue lights and a normal wave(NW)mode without blue core.The emission intensity of atom line 750.5 nm(lArⅠ750.5nm)is related to the electron density and tends to be saturated in wave coupled modes due to the neutral depletion,while the intensity of ion line 480.6 nm(IArⅡ480.6nm)is a function of the electron density and temperature,and increases dramatically as the RF power is increased.Theoretical analysis shows that TG waves are strongly damped at the plasma edge in NW and/or BC modes,while helicon waves are the dominant mechanism of power deposition or central heating of electrons in both modes.The formation of BC column mainly depends on the enhanced central electron heating by helicon waves rather than TG waves since the excitation of TG waves would be suppressed in this special anti-resonance region.
基金the project Lensless Imaging of 3D Nanostructures with Soft X-Rays(LINX)with project number P16-08 of the Perspectief research programme financed by the Dutch Research Council(NWO).
文摘Ptychographic extreme ultraviolet(EUV)diffractive imaging has emerged as a promising candidate for the next generationmetrology solutions in the semiconductor industry,as it can image wafer samples in reflection geometry at the nanoscale.This technique has surged attention recently,owing to the significant progress in high-harmonic generation(HHG)EUV sources and advancements in both hardware and software for computation.In this study,a novel algorithm is introduced and tested,which enables wavelength-multiplexed reconstruction that enhances the measurement throughput and introduces data diversity,allowing the accurate characterisation of sample structures.To tackle the inherent instabilities of the HHG source,a modal approach was adopted,which represents the crossdensity function of the illumination by a series of mutually incoherent and independent spatial modes.The proposed algorithm was implemented on a mainstream machine learning platform,which leverages automatic differentiation to manage the drastic growth in model complexity and expedites the computation using GPU acceleration.By optimising over 2oo million parameters,we demonstrate the algorithm's capacity to accommodate experimental uncertainties and achieve a resolution approaching the diffraction limit in reflection geometry.The reconstruction of wafer samples with 20-nm high patterned gold structures on a silicon substrate highlights our ability to handle complex physical interrelations involving a multitude of parameters.These results establish ptychography as an efficient and accurate metrology tool.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.12174116 and 91850107)the National Key Research and Development Program of China(Grant No.2018YFA0306200)+1 种基金Guangdong Innovative and Entrepreneurial Research Team Program(Grant No.2016ZT06C594)Science and Technology Project of Guangdong(Grant No.2020B010190001)。
文摘The ability to manipulate microlaser is highly desirable towards high-performance optoelectronic devices.Here we demonstrate feasible mode manipulation of Fabry-Perot type microlasers of a perovskite nanowire via incorporation of single gold nanoparticles.The influences of resonant wavelength,quality factor and emission directions are successively investigated using a two-dimensional finite-difference time-domain method.It is found that blueshift of resonant wavelength could be achieved together with either promoted or degraded quality factor of the microlaser via single Au NPs with varied sizes.Unidirectional emission could also be realized which is favorable for on-chip integration.Our results provide useful reference for feasible manipulation of light-matter interactions and mode selection.
基金supported in part by the National Nature Science Foundation of China under Grant 62001168in part by the Foundation and Application Research Grant of Guangzhou under Grant 202102020515.
文摘Wireless Sensor Network(WSN)is a cornerstone of Internet of Things(IoT)and has rich application scenarios.In this work,we consider a heterogeneous WSN whose sensor nodes have a diversity in their Residual Energy(RE).In this work,to protect the sensor nodes with low RE,we investigate dynamic working modes for sensor nodes which are determined by their RE and an introduced energy threshold.Besides,we employ an Unmanned Aerial Vehicle(UAV)to collect the stored data from the heterogeneous WSN.We aim to jointly optimize the cluster head selection,energy threshold and sensor nodes’working mode to minimize the weighted sum of energy con-sumption from the WSN and UAV,subject to the data collection rate constraint.To this end,we propose an efficient search method to search for an optimal energy threshold,and develop a penalty-based successive convex approximation algorithm to select the cluster heads.Then we present a low-complexity iterative approach to solve the joint optimization problem and discuss the implementation procedure.Numerical results justify that our proposed approach is able to reduce the energy consumption of the sensor nodes with low RE significantly and also saves energy for the whole WSN.
文摘BACKGROUND Acute cerebral infarction is a severe type of ischemic stroke that can be divided into anterior circulation cerebral infarction and posterior circulation cerebral infarction(PCCI).PCCI affects the structure of the posterior circulation brain,because posterior part of the brain,which has more complex anatomical structures and more prone to posterior circulation vascular variation.Therefore,improving the prognosis of PCCI patients is necessary.AIM To explore the effect of medical care linkage-continuous management mode(MCLMM)on endovascular interventional therapy(EIT)for PCCI.METHODS Sixty-nine patients with PCCI who received EIT and conventional nursing intervention were selected as the control group,and 78 patients with PCCI who received EIT and MCLMM intervention were selected as the observation group.The incidence of postoperative complications,compliance and disease selfmanagement behavior after six months of intervention,modified Rankin scale(mRS)and Barthel index(BI)scores in the acute phase and after one year of intervention,and recurrence within one year were compared between the two groups.RESULTS The total incidence rate of postoperative complications in the observation group(7.69%)was lower than that in the control group(18.84%)(P<0.05).The scores for medical compliance behavior(regular medication,appropriate diet,and rehabilitation cooperation rates)and disease self-management behavior(self-will,disease knowledge,and self-care ability)in the observation group were higher than those in the control group(P<0.05).After one year of intervention,in the observation group,the mRS score was significantly lower,and the BI score was significantly higher than those in the control group(P<0.05).The recurrence rate within one year in the observation group(3.85%)was significantly lower than that in the control group(13.04%)(P<0.05).CONCLUSION MCLMM can reduce the incidence of complications after EIT for PCCI,improve patient compliance behavior and disease self-management ability,and promote the recovery of neurological function.
基金the China Scholarship Council(202106690037)the Natural Science Foundation of Anhui Province(19080885QE194)。
文摘The trajectory tracking control performance of nonholonomic wheeled mobile robots(NWMRs)is subject to nonholonomic constraints,system uncertainties,and external disturbances.This paper proposes a barrier function-based adaptive sliding mode control(BFASMC)method to provide high-precision,fast-response performance and robustness for NWMRs.Compared with the conventional adaptive sliding mode control,the proposed control strategy can guarantee that the sliding mode variables converge to a predefined neighborhood of origin with a predefined reaching time independent of the prior knowledge of the uncertainties and disturbances bounds.Another advantage of the proposed algorithm is that the control gains can be adaptively adjusted to follow the disturbances amplitudes thanks to the barrier function.The benefit is that the overestimation of control gain can be eliminated,resulting in chattering reduction.Moreover,a modified barrier function-like control gain is employed to prevent the input saturation problem due to the physical limit of the actuator.The stability analysis and comparative experiments demonstrate that the proposed BFASMC can ensure the prespecified convergence performance of the NWMR system output variables and strong robustness against uncertainties/disturbances.
基金funded by the Ministry of Industry and Information Technology of the People’s Republic of China(Nos.[2018]473,[2019]331).
文摘Offshore engineering construction projects are large and complex,having the characteristics of multiple execution modes andmultiple resource constraints.Their complex internal scheduling processes can be regarded as resourceconstrained project scheduling problems(RCPSPs).To solve RCPSP problems in offshore engineering construction more rapidly,a hybrid genetic algorithmwas established.To solve the defects of genetic algorithms,which easily fall into the local optimal solution,a local search operation was added to a genetic algorithm to defend the offspring after crossover/mutation.Then,an elitist strategy and adaptive operators were adopted to protect the generated optimal solutions,reduce the computation time and avoid premature convergence.A calibrated function method was used to cater to the roulette rules,and appropriate rules for encoding,decoding and crossover/mutation were designed.Finally,a simple network was designed and validated using the case study of a real offshore project.The performance of the genetic algorithmand a simulated annealing algorithmwas compared to validate the feasibility and effectiveness of the approach.
