Transferring patients with critical illnesses from general wards to intensive care units (ICUs) is a crucial and time-sensitive process. This article presents strategies for improving the efficiency of patient transfe...Transferring patients with critical illnesses from general wards to intensive care units (ICUs) is a crucial and time-sensitive process. This article presents strategies for improving the efficiency of patient transfers, particularly in hospitals where intensive care units are located in buildings separate from general wards. Patient transfers comprise several steps: physicians issue orders, relatives are notified, equipment is prepared, and medical staff coordinate. We identified three factors that influence transfer time: preparation time for bed transfer, time required for shift handovers, and time required for between-ward patient movement. Unfamiliarity with transfer routes and long elevator wait times were factors that also influenced transfer time. The following strategies were proposed: develop a standardized material checklist, design key notes for patient transfers, and optimize transfer routes. These strategies reduced transfer times by 40% to 43%. This study demonstrates that by addressing logistical challenges and streamlining relevant procedures, hospitals can enhance safety and quality of care during patient transfers.展开更多
Enhancement of the nonlinear optical(NLO)output power of lasers requires urgent development of an NLO crystal with a significant second-harmonic generation(SHG)response and sufficient birefringence for phase-matching ...Enhancement of the nonlinear optical(NLO)output power of lasers requires urgent development of an NLO crystal with a significant second-harmonic generation(SHG)response and sufficient birefringence for phase-matching capability;however,simultaneously optimizing these two key parameters remains a great challenge.In contrast to traditional single-anion units,the stereochemically-active lone pair Sb^(3+)ion is coordinated by S^(2-)and I^(-) ions to yield the mixed-anionic Sb SI chalcohalide that can enhance hyperpolarizability and anisotropic polarizability concurrently.As anticipated,Sb SI exhibited the largest SHG response(5.7×Ag Ga S_(2)@1.91μm)among phase-matching Sb-based sulfides,the favorable laser-induced damage threshold(LIDT,2.3×Ag Ga S_(2)@2.09μm),and the giant calculated birefringence(0.62@1.91μm).Structural analysis and computational simulations indicate that the highly polarizable mixed anion determine the enormous SHG response and birefringence.展开更多
Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispat...Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispatching.Data-driven diagnostic methods often fail to account for the imbalanced distribution of data samples,leading to reduced classification performance in diagnosing load deviations in USC units.To address the class imbalance issue in USC load deviation datasets,this study proposes a diagnostic method based on the multi-label natural neighbor boundary oversampling technique(MLNaNBDOS).The method is articulated in three phases.Initially,the traditional binary oversampling strategy is improved by constructing a binary multi-label relationship for the load deviations in coal-fired units.Subsequently,an adaptive adjustment of the oversampling factor is implemented to determine the oversampling weight for each sample class.Finally,the generation of new instances is refined by dynamically evaluating the similarity between new cases and natural neighbors through a random factor,ensuring precise control over the instance generation process.In comparisons with nine benchmark methods across three imbalanced USC load deviation datasets,the proposed method demonstrates superior performance on several key evaluation metrics,including Micro-F1,Micro-G-mean,and Hamming Loss,with average values of 0.8497,0.9150,and 0.1503,respectively.These results substantiate the effectiveness of the proposed method in accurately diagnosing the sources of load deviations in USC units.展开更多
Coking at the fractionating tower bottom and the decant oil circulation system disrupts the heat balance,leading to unplanned shutdown and destroying the long period stable operation of the Fluid Catalytic Cracking Un...Coking at the fractionating tower bottom and the decant oil circulation system disrupts the heat balance,leading to unplanned shutdown and destroying the long period stable operation of the Fluid Catalytic Cracking Unit(FCCU).The FCCU operates through interconnected subsystems,generating high-dimensional,nonlinear,and non-stationary data characterized by spatiotemporally correlated.The decant oil solid content is the crucial indicator for monitoring catalyst loss from the reactor-regenerator system and coking risk tendency at the fractionating tower bottom that relies on sampling and laboratory testing,which is lagging responsiveness and labor-intensive.Developing the online decant oil solid content soft sensor using industrial data to support operators in conducting predictive maintenance is essential.Therefore,this paper proposes a hybrid deep learning framework for soft sensor development that combines spatiotemporal pattern extraction with interpretability,enabling accurate risk identification in dynamic operational conditions.This framework employs a Filter-Wrapper method for dimensionality reduction,followed by a 2D Convolutional Neural Network(2DCNN)for extracting spatial patterns,and a Bidirectional Gated Recurrent Unit(BiGRU)for capturing long-term temporal dependencies,with an Attention Mechanism(AM)to highlight critical features adaptively.The integration of SHapley Additive exPlanations(SHAP),Complementary Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN),2DCNN,and expert knowledge precisely quantifies feature contributions and decomposes signals,significantly enhancing the practicality of risk identification.Applied to a China refinery with processing capacity of 2.80×10^(6) t/a,the soft sensor achieved the R^(2) value of 0.93 and five-level risk identification accuracy of 96.42%.These results demonstrate the framework's accuracy,robustness,and suitability for complex industrial scenarios,advancing risk visualization and management.展开更多
The Wufeng-Longmaxi marine shale in the Eastern Sichuan Basin is the key target for shale gas exploration in China.Based on logging response and lithofacies type,three paleo-geomorphological units are identified in th...The Wufeng-Longmaxi marine shale in the Eastern Sichuan Basin is the key target for shale gas exploration in China.Based on logging response and lithofacies type,three paleo-geomorphological units are identified in the deep-water shelf during the Wufeng-Longmaxi deposition:subaqueous slope(SS),subaqueous plain(SP),and subaqueous sub-sag(SSS).Using methods such as mercury intrusion porosimetry(MIP),field emission scanning electron microscopy(FE-SEM),nuclear magnetic resonance(NMR),and X-ray diffraction(XRD),the differences of environmental conditions,mineral composition,organic matter(OM)content,and pore structure in different units are determined,and the factors controlling the differences in shale reservoirs are discussed.The results show that redox conditions of bottom water and productivity of surface water affect OM enrichment,resulting in SSS being the most organic-rich unit.Terrigenous detrital input affects mineral composition in different units,and SSS is the most quartz-rich unit.From SS to SSS shale,the proportion of OM pores gradually increased,while the proportion of inorganic pores and microfractures gradually decreased.The pore size distribution dominated by mesopores in SP and SSS shale is generally consistent,much higher than in SS.The differences in sedimentary environments result in differences in reservoir quality.The OM and brittle mineral content in SSS are relatively high,which is beneficial for reservoir development.SSS has the best environmental conditions;therefore,the quality of the marine shale reservoirs formed is the best.展开更多
Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluct...Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.展开更多
The integration of large-scale renewable energy introduces frequency instability challenges due to inherent intermittency.While doubly-fed pumped storage units(DFPSUs)offer frequency regulation potential in pumping mo...The integration of large-scale renewable energy introduces frequency instability challenges due to inherent intermittency.While doubly-fed pumped storage units(DFPSUs)offer frequency regulation potential in pumping mode,conventional strategies fail to address hydraulic-mechanical coupling dynamics and operational constraints,limiting their effectiveness.This paper presents an innovative primary frequency control strategy for double-fed pumped storage units(DFPSUs)operating in pumpingmode,integrating an adaptive parameter calculation method.This method is constrained by operational speed and power limits,addressing key performance factors.A dynamic model that incorporates the reversible pump-turbine characteristics is developed to translate frequency deviations into coordinated adjustments in speed and power during pumping operations.The research thoroughly analyzes the influence of control parameters on the frequency response dynamics.Additionally,the paper introduces a deep reinforcement learning(DRL)-based optimization framework,which enables real-time tuning of control parameters in response to changing rotor speed and frequency states.This method strategicallymanages the utilization of kinetic energy while ensuring compliance with operational safety constraints.The effectiveness of the proposed strategy is validated through simulation studies conducted on a four-machine,two-area DFPSU system.These studies demonstrate the strategy’s potential for improving frequency regulation performance under a variety of operating conditions,highlighting its effectiveness in optimizing energy storage and frequency control in power grids.展开更多
In high-renewable-energy power systems,the demand for fast-responding capabilities is growing.To address the limitations of conventional closed-loop frequency control,where the integral coefficient cannot dynamically ...In high-renewable-energy power systems,the demand for fast-responding capabilities is growing.To address the limitations of conventional closed-loop frequency control,where the integral coefficient cannot dynamically adjust the frequency regulation command based on the state of charge(SoC)of energy storage units,this paper proposes a secondary frequency regulation control strategy based on variable integral coefficients for multiple energy storage units.First,a power-uniform controller is designed to ensure that thermal power units gradually take on more regulation power during the frequency regulation process.Next,a control framework based on variable integral coefficients is proposed within the secondary frequency regulation model,along with an objective function that simultaneously considers both Automatic Generation Control(AGC)command tracking performance and SoC recovery requirements of energy storage units.Finally,a gradient descent optimization method is used to dynamically adjust the gain of the energy storage integral controller,allowingmultiple energy storage units to respond in real-time to AGC instructions and SoC variations.Simulation results confirmthe effectiveness of the proposedmethod.Compared to traditional strategies,the proposed approach takes into account the SoCdiscrepancies amongmultiple energy storage units and the duration of system net power imbalances.It successfully implements secondary frequency regulation while achieving dynamic power allocation among the units.展开更多
BACKGROUND Parental presence in neonatal units(NUs)is essential for infant development and family well-being.A deeper understanding of the factors influencing parental presence is vital and will contribute to the deve...BACKGROUND Parental presence in neonatal units(NUs)is essential for infant development and family well-being.A deeper understanding of the factors influencing parental presence is vital and will contribute to the development of targeted interventions and policies that enhance parental engagement in neonatal care,thereby improving outcomes for infants and their families.AIM To identify and analyze primary factors influencing parental involvement in their child’s care in a neonatal intensive care unit(NICU).METHODS A literature search was conducted using the PubMed,MEDLINE,and Cochrane Library for systematic reviews databases,with the following search terms:“parental presence neonatology”,“couplet care”,“zero separation neonatal care”,“family integrated care”,“couplet care intervention”,“mother-child separation”,“parents newborn togetherness”,“mother-baby care”,“closeness and separation NICU”,“mother-infant interaction NICU”,“kangaroo care”,“dyad mother-infant”,and“newborn integrated care”.The database search for this literature review began on December 10,2024,with the final search conducted on April 10,2025.RESULTS The literature search yielded 281 articles,out of which 23 were selected for a detailed review.The factors associated with parental presence in NUs were grouped into five main categories:Parents’socio-demographic and cultural traits;the physical layout and care model of the NUs;the quality of parents’relationships with the healthcare staff;their active involvement in neonatal care;and the newborn’s health status.CONCLUSION The identification of factors that affect parental presence in NUs is critical for developing effective strategies aimed at encouraging increased parental involvement and ultimately improving neonatal and family outcomes.展开更多
The rise of the aging population parallels the rapidly increasing cases of neurological disorders. This puts pressure on scientists and physicians to find novel methods that can prevent and treat neurodegeneration. Th...The rise of the aging population parallels the rapidly increasing cases of neurological disorders. This puts pressure on scientists and physicians to find novel methods that can prevent and treat neurodegeneration. The brain is made up of a complex network of different cell types that work in tandem to maintain systemic homeostasis.展开更多
The face velocities of the high efficiency particulate air filters and the ultra low penetration airfilters in fan filter units (FFUs) have large relative standard deviation and turbulivity. It seriously affects the ...The face velocities of the high efficiency particulate air filters and the ultra low penetration airfilters in fan filter units (FFUs) have large relative standard deviation and turbulivity. It seriously affects the unidirectivity of the flow in the unidirectional flow clean zone and cleanroom. The cross contamination in this kind of unidirectional flow area is hardly controlled. It is significant to find optional method for keeping the face velocity uniformity of FFU and reducing the face velocity turbulivity of FFU, furthermore, to keep the cleanliness level under FFUs. The normal and easy method is to add flow rectifiers under filters. FFUs with various flow rectifiers have been tested. The uniformity and turbulivity of facevelocity under the FFU are presented in this paper. The influence of the facevelocity uniformity and turbulivity on the contamination boundary of the unidirectional flow is studiedas well.展开更多
Using the characteristic of addition of information quantity and the principle of equivalence of information quantity, this paper derives the general conversion formulae of the formation theory method conversion (synt...Using the characteristic of addition of information quantity and the principle of equivalence of information quantity, this paper derives the general conversion formulae of the formation theory method conversion (synthesis) on the systems consisting of different success failure model units. According to the fundamental method of the unit reliability assessment, the general models of system reliability approximate lower limits are given. Finally, this paper analyses the application of the assessment method by examples, the assessment results are neither conservative nor radical and very satisfactory. The assessment method can be popularized to the systems which have fixed reliability structural models.展开更多
A universal thermodynamic model of calculating mass action concentrations for structural units or ion couples in ternary and binary strong electrolyte aqueous solution was developed based on the ion and molecule coexi...A universal thermodynamic model of calculating mass action concentrations for structural units or ion couples in ternary and binary strong electrolyte aqueous solution was developed based on the ion and molecule coexistence theory and verified in four kinds of binary aqueous solutions and two kinds of ternary aqueous solutions. The calculated mass action concentrations of structural units or ion couples in four binary aqueous solutions and two ternary solutions at 298.15 K have good agreement with the reported activity data from literatures after shifting the standard state and concentration unit. Therefore, the calculated mass action concentrations of structural units or ion couples from the developed universal thermodynamic model for ternary and binary aqueous solutions can be applied to predict reaction ability of components in ternary and binary strong electrolyte aqueous solutions. It is also proved that the assumptions applied in the developed thermodynamic model are correct and reasonable, i.e., strong electrolyte aqueous solution is composed of cations and anions as simple ions, H2O as simple molecule and other hydrous salt compounds as complex molecules. The calculated mass action concentrations of structural units or ion couples in ternary and binary strong electrolyte aqueous solutions strictly follow the mass action law.展开更多
The present status of self-elevating drilling units was analysed. Based on statistics of the main dimensions of self-elevating drilling units, a mathematical model was established using stepwise return procedures and ...The present status of self-elevating drilling units was analysed. Based on statistics of the main dimensions of self-elevating drilling units, a mathematical model was established using stepwise return procedures and a back-propagation neural network. mathematical model is applicable and reliable. The of the main dimensions of self-elevating drilling Analysis of examples of calculations showed that the model is useful for mastering the essential variations units and can be used for technical and economic analysis as well as in conceptual designs of drilling units.展开更多
文摘Transferring patients with critical illnesses from general wards to intensive care units (ICUs) is a crucial and time-sensitive process. This article presents strategies for improving the efficiency of patient transfers, particularly in hospitals where intensive care units are located in buildings separate from general wards. Patient transfers comprise several steps: physicians issue orders, relatives are notified, equipment is prepared, and medical staff coordinate. We identified three factors that influence transfer time: preparation time for bed transfer, time required for shift handovers, and time required for between-ward patient movement. Unfamiliarity with transfer routes and long elevator wait times were factors that also influenced transfer time. The following strategies were proposed: develop a standardized material checklist, design key notes for patient transfers, and optimize transfer routes. These strategies reduced transfer times by 40% to 43%. This study demonstrates that by addressing logistical challenges and streamlining relevant procedures, hospitals can enhance safety and quality of care during patient transfers.
基金supported by the National Natural Science Foundation of China(Nos.21921001,22075283,92161125,22175172,21827813,U21A20508)the Youth Innovation Promotion Association of Chinese Academy of Sciences(Nos.2020303,2021300)the Fujian Science&Technology Innovation Laboratory for Optoelectronic Information of China(No.2020ZZ108)。
文摘Enhancement of the nonlinear optical(NLO)output power of lasers requires urgent development of an NLO crystal with a significant second-harmonic generation(SHG)response and sufficient birefringence for phase-matching capability;however,simultaneously optimizing these two key parameters remains a great challenge.In contrast to traditional single-anion units,the stereochemically-active lone pair Sb^(3+)ion is coordinated by S^(2-)and I^(-) ions to yield the mixed-anionic Sb SI chalcohalide that can enhance hyperpolarizability and anisotropic polarizability concurrently.As anticipated,Sb SI exhibited the largest SHG response(5.7×Ag Ga S_(2)@1.91μm)among phase-matching Sb-based sulfides,the favorable laser-induced damage threshold(LIDT,2.3×Ag Ga S_(2)@2.09μm),and the giant calculated birefringence(0.62@1.91μm).Structural analysis and computational simulations indicate that the highly polarizable mixed anion determine the enormous SHG response and birefringence.
基金supported by the National Natural Science Foundation of China(Grant No.62173050)Shenzhen Municipal Science and Technology Innovation Committee(Grant No.KCXFZ20211020165004006)+3 种基金Natural Science Foundation of Hunan Province of China(Grant No.2023JJ30051)Hunan Provincial Graduate Student Research Innovation Project(Grant No.QL20230214)Major Scientific and Technological Innovation Platform Project of Hunan Province(2024JC1003)Hunan Provincial University Students’Energy Conservation and Emission Reduction Innovation and Entrepreneurship Education Center(Grant No.2019-10).
文摘Load deviations between the output of ultra-supercritical(USC)coal-fired power units and automatic generation control(AGC)commands can adversely affect the safe and stable operation of these units and grid load dispatching.Data-driven diagnostic methods often fail to account for the imbalanced distribution of data samples,leading to reduced classification performance in diagnosing load deviations in USC units.To address the class imbalance issue in USC load deviation datasets,this study proposes a diagnostic method based on the multi-label natural neighbor boundary oversampling technique(MLNaNBDOS).The method is articulated in three phases.Initially,the traditional binary oversampling strategy is improved by constructing a binary multi-label relationship for the load deviations in coal-fired units.Subsequently,an adaptive adjustment of the oversampling factor is implemented to determine the oversampling weight for each sample class.Finally,the generation of new instances is refined by dynamically evaluating the similarity between new cases and natural neighbors through a random factor,ensuring precise control over the instance generation process.In comparisons with nine benchmark methods across three imbalanced USC load deviation datasets,the proposed method demonstrates superior performance on several key evaluation metrics,including Micro-F1,Micro-G-mean,and Hamming Loss,with average values of 0.8497,0.9150,and 0.1503,respectively.These results substantiate the effectiveness of the proposed method in accurately diagnosing the sources of load deviations in USC units.
基金supported by the Innovative Research Group Project of the National Natural Science Foundation of China(22021004)Sinopec Major Science and Technology Projects(321123-1)。
文摘Coking at the fractionating tower bottom and the decant oil circulation system disrupts the heat balance,leading to unplanned shutdown and destroying the long period stable operation of the Fluid Catalytic Cracking Unit(FCCU).The FCCU operates through interconnected subsystems,generating high-dimensional,nonlinear,and non-stationary data characterized by spatiotemporally correlated.The decant oil solid content is the crucial indicator for monitoring catalyst loss from the reactor-regenerator system and coking risk tendency at the fractionating tower bottom that relies on sampling and laboratory testing,which is lagging responsiveness and labor-intensive.Developing the online decant oil solid content soft sensor using industrial data to support operators in conducting predictive maintenance is essential.Therefore,this paper proposes a hybrid deep learning framework for soft sensor development that combines spatiotemporal pattern extraction with interpretability,enabling accurate risk identification in dynamic operational conditions.This framework employs a Filter-Wrapper method for dimensionality reduction,followed by a 2D Convolutional Neural Network(2DCNN)for extracting spatial patterns,and a Bidirectional Gated Recurrent Unit(BiGRU)for capturing long-term temporal dependencies,with an Attention Mechanism(AM)to highlight critical features adaptively.The integration of SHapley Additive exPlanations(SHAP),Complementary Ensemble Empirical Mode Decomposition with Adaptive Noise(CEEMDAN),2DCNN,and expert knowledge precisely quantifies feature contributions and decomposes signals,significantly enhancing the practicality of risk identification.Applied to a China refinery with processing capacity of 2.80×10^(6) t/a,the soft sensor achieved the R^(2) value of 0.93 and five-level risk identification accuracy of 96.42%.These results demonstrate the framework's accuracy,robustness,and suitability for complex industrial scenarios,advancing risk visualization and management.
基金the National Natural Science Foundation of China,China(No.42272171)National Natural Science Foundation of China,China(No.42302166)Science and Technology Cooperation Project of the CNPCSWPU Innovation Alliance Q3(Grant No.2020CX030101)。
文摘The Wufeng-Longmaxi marine shale in the Eastern Sichuan Basin is the key target for shale gas exploration in China.Based on logging response and lithofacies type,three paleo-geomorphological units are identified in the deep-water shelf during the Wufeng-Longmaxi deposition:subaqueous slope(SS),subaqueous plain(SP),and subaqueous sub-sag(SSS).Using methods such as mercury intrusion porosimetry(MIP),field emission scanning electron microscopy(FE-SEM),nuclear magnetic resonance(NMR),and X-ray diffraction(XRD),the differences of environmental conditions,mineral composition,organic matter(OM)content,and pore structure in different units are determined,and the factors controlling the differences in shale reservoirs are discussed.The results show that redox conditions of bottom water and productivity of surface water affect OM enrichment,resulting in SSS being the most organic-rich unit.Terrigenous detrital input affects mineral composition in different units,and SSS is the most quartz-rich unit.From SS to SSS shale,the proportion of OM pores gradually increased,while the proportion of inorganic pores and microfractures gradually decreased.The pore size distribution dominated by mesopores in SP and SSS shale is generally consistent,much higher than in SS.The differences in sedimentary environments result in differences in reservoir quality.The OM and brittle mineral content in SSS are relatively high,which is beneficial for reservoir development.SSS has the best environmental conditions;therefore,the quality of the marine shale reservoirs formed is the best.
基金supported by the National Natural Science Foundation of China(Project No.52377082)the Scientific Research Program of Jilin Provincial Department of Education(Project No.JJKH20230123KJ).
文摘Large-scale new energy grid connection leads to the weakening of the system frequency regulation capability,and the system frequency stability is facing unprecedented challenges.In order to solve rapid frequency fluctuation caused by new energy units,this paper proposes a new energy power system frequency regulation strategy with multiple units including the doubly-fed pumped storage unit(DFPSU).Firstly,based on the model predictive control(MPC)theory,the state space equations are established by considering the operating characteristics of the units and the dynamic behavior of the system;secondly,the proportional-differential control link is introduced to minimize the frequency deviation to further optimize the frequency modulation(FM)output of the DFPSU and inhibit the rapid fluctuation of the frequency;lastly,it is verified on theMatlab/Simulink simulation platform,and the results show that the model predictive control with proportional-differential control link can further release the FM potential of the DFPSU,increase the depth of its FM,effectively reduce the frequency deviation of the system and its rate of change,realize the optimization of the active output of the DFPSU and that of other units,and improve the frequency response capability of the system.
文摘The integration of large-scale renewable energy introduces frequency instability challenges due to inherent intermittency.While doubly-fed pumped storage units(DFPSUs)offer frequency regulation potential in pumping mode,conventional strategies fail to address hydraulic-mechanical coupling dynamics and operational constraints,limiting their effectiveness.This paper presents an innovative primary frequency control strategy for double-fed pumped storage units(DFPSUs)operating in pumpingmode,integrating an adaptive parameter calculation method.This method is constrained by operational speed and power limits,addressing key performance factors.A dynamic model that incorporates the reversible pump-turbine characteristics is developed to translate frequency deviations into coordinated adjustments in speed and power during pumping operations.The research thoroughly analyzes the influence of control parameters on the frequency response dynamics.Additionally,the paper introduces a deep reinforcement learning(DRL)-based optimization framework,which enables real-time tuning of control parameters in response to changing rotor speed and frequency states.This method strategicallymanages the utilization of kinetic energy while ensuring compliance with operational safety constraints.The effectiveness of the proposed strategy is validated through simulation studies conducted on a four-machine,two-area DFPSU system.These studies demonstrate the strategy’s potential for improving frequency regulation performance under a variety of operating conditions,highlighting its effectiveness in optimizing energy storage and frequency control in power grids.
文摘In high-renewable-energy power systems,the demand for fast-responding capabilities is growing.To address the limitations of conventional closed-loop frequency control,where the integral coefficient cannot dynamically adjust the frequency regulation command based on the state of charge(SoC)of energy storage units,this paper proposes a secondary frequency regulation control strategy based on variable integral coefficients for multiple energy storage units.First,a power-uniform controller is designed to ensure that thermal power units gradually take on more regulation power during the frequency regulation process.Next,a control framework based on variable integral coefficients is proposed within the secondary frequency regulation model,along with an objective function that simultaneously considers both Automatic Generation Control(AGC)command tracking performance and SoC recovery requirements of energy storage units.Finally,a gradient descent optimization method is used to dynamically adjust the gain of the energy storage integral controller,allowingmultiple energy storage units to respond in real-time to AGC instructions and SoC variations.Simulation results confirmthe effectiveness of the proposedmethod.Compared to traditional strategies,the proposed approach takes into account the SoCdiscrepancies amongmultiple energy storage units and the duration of system net power imbalances.It successfully implements secondary frequency regulation while achieving dynamic power allocation among the units.
文摘BACKGROUND Parental presence in neonatal units(NUs)is essential for infant development and family well-being.A deeper understanding of the factors influencing parental presence is vital and will contribute to the development of targeted interventions and policies that enhance parental engagement in neonatal care,thereby improving outcomes for infants and their families.AIM To identify and analyze primary factors influencing parental involvement in their child’s care in a neonatal intensive care unit(NICU).METHODS A literature search was conducted using the PubMed,MEDLINE,and Cochrane Library for systematic reviews databases,with the following search terms:“parental presence neonatology”,“couplet care”,“zero separation neonatal care”,“family integrated care”,“couplet care intervention”,“mother-child separation”,“parents newborn togetherness”,“mother-baby care”,“closeness and separation NICU”,“mother-infant interaction NICU”,“kangaroo care”,“dyad mother-infant”,and“newborn integrated care”.The database search for this literature review began on December 10,2024,with the final search conducted on April 10,2025.RESULTS The literature search yielded 281 articles,out of which 23 were selected for a detailed review.The factors associated with parental presence in NUs were grouped into five main categories:Parents’socio-demographic and cultural traits;the physical layout and care model of the NUs;the quality of parents’relationships with the healthcare staff;their active involvement in neonatal care;and the newborn’s health status.CONCLUSION The identification of factors that affect parental presence in NUs is critical for developing effective strategies aimed at encouraging increased parental involvement and ultimately improving neonatal and family outcomes.
文摘The rise of the aging population parallels the rapidly increasing cases of neurological disorders. This puts pressure on scientists and physicians to find novel methods that can prevent and treat neurodegeneration. The brain is made up of a complex network of different cell types that work in tandem to maintain systemic homeostasis.
文摘The face velocities of the high efficiency particulate air filters and the ultra low penetration airfilters in fan filter units (FFUs) have large relative standard deviation and turbulivity. It seriously affects the unidirectivity of the flow in the unidirectional flow clean zone and cleanroom. The cross contamination in this kind of unidirectional flow area is hardly controlled. It is significant to find optional method for keeping the face velocity uniformity of FFU and reducing the face velocity turbulivity of FFU, furthermore, to keep the cleanliness level under FFUs. The normal and easy method is to add flow rectifiers under filters. FFUs with various flow rectifiers have been tested. The uniformity and turbulivity of facevelocity under the FFU are presented in this paper. The influence of the facevelocity uniformity and turbulivity on the contamination boundary of the unidirectional flow is studiedas well.
文摘Using the characteristic of addition of information quantity and the principle of equivalence of information quantity, this paper derives the general conversion formulae of the formation theory method conversion (synthesis) on the systems consisting of different success failure model units. According to the fundamental method of the unit reliability assessment, the general models of system reliability approximate lower limits are given. Finally, this paper analyses the application of the assessment method by examples, the assessment results are neither conservative nor radical and very satisfactory. The assessment method can be popularized to the systems which have fixed reliability structural models.
基金Project supported by Publication Foundation of National Science and Technology Academic Books of China
文摘A universal thermodynamic model of calculating mass action concentrations for structural units or ion couples in ternary and binary strong electrolyte aqueous solution was developed based on the ion and molecule coexistence theory and verified in four kinds of binary aqueous solutions and two kinds of ternary aqueous solutions. The calculated mass action concentrations of structural units or ion couples in four binary aqueous solutions and two ternary solutions at 298.15 K have good agreement with the reported activity data from literatures after shifting the standard state and concentration unit. Therefore, the calculated mass action concentrations of structural units or ion couples from the developed universal thermodynamic model for ternary and binary aqueous solutions can be applied to predict reaction ability of components in ternary and binary strong electrolyte aqueous solutions. It is also proved that the assumptions applied in the developed thermodynamic model are correct and reasonable, i.e., strong electrolyte aqueous solution is composed of cations and anions as simple ions, H2O as simple molecule and other hydrous salt compounds as complex molecules. The calculated mass action concentrations of structural units or ion couples in ternary and binary strong electrolyte aqueous solutions strictly follow the mass action law.
基金Supported by the National 863 Plan Foundation under Grant No.2003AA414060
文摘The present status of self-elevating drilling units was analysed. Based on statistics of the main dimensions of self-elevating drilling units, a mathematical model was established using stepwise return procedures and a back-propagation neural network. mathematical model is applicable and reliable. The of the main dimensions of self-elevating drilling Analysis of examples of calculations showed that the model is useful for mastering the essential variations units and can be used for technical and economic analysis as well as in conceptual designs of drilling units.
