期刊文献+
共找到39,686篇文章
< 1 2 250 >
每页显示 20 50 100
Long non-coding RNA H19 regulates neurogenesis of induced neural stem cells in a mouse model of closed head injury 被引量:3
1
作者 Mou Gao Qin Dong +4 位作者 Zhijun Yang Dan Zou Yajuan Han Zhanfeng Chen Ruxiang Xu 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第4期872-880,共9页
Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regen... Stem cell-based therapies have been proposed as a potential treatment for neural regeneration following closed head injury.We previously reported that induced neural stem cells exert beneficial effects on neural regeneration via cell replacement.However,the neural regeneration efficiency of induced neural stem cells remains limited.In this study,we explored differentially expressed genes and long non-coding RNAs to clarify the mechanism underlying the neurogenesis of induced neural stem cells.We found that H19 was the most downregulated neurogenesis-associated lnc RNA in induced neural stem cells compared with induced pluripotent stem cells.Additionally,we demonstrated that H19 levels in induced neural stem cells were markedly lower than those in induced pluripotent stem cells and were substantially higher than those in induced neural stem cell-derived neurons.We predicted the target genes of H19 and discovered that H19 directly interacts with mi R-325-3p,which directly interacts with Ctbp2 in induced pluripotent stem cells and induced neural stem cells.Silencing H19 or Ctbp2 impaired induced neural stem cell proliferation,and mi R-325-3p suppression restored the effect of H19 inhibition but not the effect of Ctbp2 inhibition.Furthermore,H19 silencing substantially promoted the neural differentiation of induced neural stem cells and did not induce apoptosis of induced neural stem cells.Notably,silencing H19 in induced neural stem cell grafts markedly accelerated the neurological recovery of closed head injury mice.Our results reveal that H19 regulates the neurogenesis of induced neural stem cells.H19 inhibition may promote the neural differentiation of induced neural stem cells,which is closely associated with neurological recovery following closed head injury. 展开更多
关键词 closed head injury Ctbp2 induced neural stem cell lncRNA H19 miR-325-3p NEUROGENESIS
下载PDF
Research on perturbation of neutron fluence rate in a closed thermal neutron field due to medium materials
2
作者 Jun-Kai Yang Ping-Quan Wang +8 位作者 Zhi-Meng Hu Fan Li Jun-Mei Zeng Lin Xiao Hong-Yu Guo Jian Zhang Giuseppe Gorini Hui Zhang Chungming Paul Chu 《Nuclear Science and Techniques》 SCIE EI CAS CSCD 2024年第10期222-232,共11页
The neutron radiation field has vital applications in areas such as biomedicine,geology,radiation safety,and many others for neutron detection and neutron metrology.Correcting neutron fluence rate perturbation accurat... The neutron radiation field has vital applications in areas such as biomedicine,geology,radiation safety,and many others for neutron detection and neutron metrology.Correcting neutron fluence rate perturbation accurately is an important yet challenging problem.This study proposes a correction method that analyzes three physical processes.This method,which transforms the detection process from point detection to area detection,is based on a novel physical model and has been validated through theoretical analyses,experiments,and simulations.According to the average differences between the calculated and experimental results,the new method(1.67%)demonstrated better accuracy than the traditional simulation(2.17%).In a closed thermal neutron radiation field,the detector or strong neutron absorption material significantly perturbs the neutron fluence rate,whereas its impact on the energy spectrum shape and neutron directionality is relatively minor.Furthermore,based on the calculation results of the perturbation rate formula for medium materials with different compositions and sizes,the larger the volume and capture cross section of the medium,the higher the perturbation rate generated in the closed radiation field. 展开更多
关键词 Perturbation rate Area detection Three-dimensional neutron energy spectrum closed radiation field
下载PDF
Induced neural stem cells regulate microglial activation through Akt-mediated upregulation of CXCR4 and Crry in a mouse model of closed head injury
3
作者 Mou Gao Qin Dong +3 位作者 Dan Zou Zhijun Yang Lili Guo Ruxiang Xu 《Neural Regeneration Research》 SCIE CAS 2025年第5期1416-1430,共15页
Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells ... Microglial activation that occurs rapidly after closed head injury may play important and complex roles in neuroinflammation-associated neuronal damage and repair.We previously reported that induced neural stem cells can modulate the behavior of activated microglia via CXCL12/CXCR4 signaling,influencing their activation such that they can promote neurological recovery.However,the mechanism of CXCR4 upregulation in induced neural stem cells remains unclear.In this study,we found that nuclear factor-κB activation induced by closed head injury mouse serum in microglia promoted CXCL12 and tumor necrosis factor-αexpression but suppressed insulin-like growth factor-1 expression.However,recombinant complement receptor 2-conjugated Crry(CR2-Crry)reduced the effects of closed head injury mouse serum-induced nuclear factor-κB activation in microglia and the levels of activated microglia,CXCL12,and tumor necrosis factor-α.Additionally,we observed that,in response to stimulation(including stimulation by CXCL12 secreted by activated microglia),CXCR4 and Crry levels can be upregulated in induced neural stem cells via the interplay among CXCL12/CXCR4,Crry,and Akt signaling to modulate microglial activation.In agreement with these in vitro experimental results,we found that Akt activation enhanced the immunoregulatory effects of induced neural stem cell grafts on microglial activation,leading to the promotion of neurological recovery via insulin-like growth factor-1 secretion and the neuroprotective effects of induced neural stem cell grafts through CXCR4 and Crry upregulation in the injured cortices of closed head injury mice.Notably,these beneficial effects of Akt activation in induced neural stem cells were positively correlated with the therapeutic effects of induced neural stem cells on neuronal injury,cerebral edema,and neurological disorders post–closed head injury.In conclusion,our findings reveal that Akt activation may enhance the immunoregulatory effects of induced neural stem cells on microglial activation via upregulation of CXCR4 and Crry,thereby promoting induced neural stem cell–mediated improvement of neuronal injury,cerebral edema,and neurological disorders following closed head injury. 展开更多
关键词 Akt signaling cerebral edema closed head injury Crry CXCR4 induced neural stem cell MICROGLIA NEUROINFLAMMATION
下载PDF
On Fuzzy Regularly Closed Filters in Michálek Fuzzy Topological Space
4
作者 Puthenpurackal Ratnakumar Neethu Bloomy Joseph 《Advances in Pure Mathematics》 2024年第10期779-784,共6页
C.L. Chang’s introduction of fuzzy topology in 1981 opened up new avenues for parallel theories in topology. However, Chang’s work appears to focus more on the topology of fuzzy sets rather than fuzzy topology itsel... C.L. Chang’s introduction of fuzzy topology in 1981 opened up new avenues for parallel theories in topology. However, Chang’s work appears to focus more on the topology of fuzzy sets rather than fuzzy topology itself. In 1975, Michálek presented a functional definition of ordinary topology and later developed fuzzy topology as a distinct extension of this idea, setting it apart from Chang’s approach. While there has been significant research on Chang’s fuzzy topology, Michálek’s version has not received as much attention. This paper introduces the concept of fuzzy regularly closed filters, or FRCM filters, within Michálek’s fuzzy topological space and explores some properties of FRCM ultrafilters. 展开更多
关键词 TOPOLOGY Fuzzy Topology Michálek’s Fuzzy Topological Space Fuzzy closed Fuzzy Open FILTERS
下载PDF
Sensing-Communication-Computing-Control Closed Loop for NOMA-UAV Systems
5
作者 Lei Chengleyang Feng Wei +4 位作者 Wang Jue Wang Yanmin Jin Shi Yin Liuguo Ge Ning 《China Communications》 SCIE CSCD 2024年第8期89-103,共15页
In the areas without terrestrial communication infrastructures,unmanned aerial vehicles(UAVs)can be utilized to serve field robots for mission-critical tasks.For this purpose,UAVs can be equipped with sensing,communic... In the areas without terrestrial communication infrastructures,unmanned aerial vehicles(UAVs)can be utilized to serve field robots for mission-critical tasks.For this purpose,UAVs can be equipped with sensing,communication,and computing modules to support various requirements of robots.In the task process,different modules assist the robots to perform tasks in a closed-loop way,which is referred to as a sensing-communication-computing-control(SC3)loop.In this work,we investigate a UAV-aided system containing multiple SC^(3)loops,which leverages non-orthogonal multiple access(NOMA)for efficient resource sharing.We describe and compare three different modelling levels for the SC^(3)loop.Based on the entropy SC^(3)loop model,a sum linear quadratic regulator(LQR)control cost minimization problem is formulated by optimizing the communication power.Further for the assure-to-be-stable case,we show that the original problem can be approximated by a modified user fairness problem,and accordingly gain more insights into the optimal solutions.Simulation results demonstrate the performance gain of using NOMA in such task-oriented systems,as well as the superiority of our proposed closed-loop-oriented design. 展开更多
关键词 closed loop linear quadratic regulator(LQR) non-orthogonal multiple access(NOMA) power allocation unmanned aerial vehicle(UAV)
下载PDF
Simulation Modelling and Techno-Economics of Supercritical Carbon Dioxide Recompression Closed Brayton Cycle
6
作者 Ken Amaale Atinga 《Energy and Power Engineering》 2024年第10期325-344,共20页
In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential inve... In recent years, there has been global interest in meeting targets relating to energy affordability and security while taking into account greenhouse gas emissions. This has heightened major interest in potential investigations into the use of supercritical carbon dioxide (sCO2) power cycles. Climate change mitigation is the ultimate driver for this increased interest;other relevant issues include the potential for high cycle efficiency and a circular economy. In this study, a 25 MWe recompression closed Brayton cycle (RCBC) has been assessed, and sCO2 has been proposed as the working fluid for the power plant. The methodology used in this research work comprises thermodynamic and techno-economic analysis for the prospective commercialization of this sCO2 power cycle. An evaluated estimation of capital expenditure, operational expenditure, and cost of electricity has been considered in this study. The ASPEN Plus simulation results have been compared with theoretical and mathematical calculations to assess the performance of the compressors, turbine, and heat exchangers. The results thus reveal that the cycle efficiency for this prospective sCO2 recompression closed Brayton cycle increases (39% - 53.6%) as the temperature progressively increases from 550˚C to 900˚C. Data from the Aspen simulation model was used to aid the cost function calculations to estimate the total capital investment cost of the plant. Also, the techno-economic results have shown less cost for purchasing equipment due to fewer components being required for the cycle configuration as compared to the conventional steam power plant. 展开更多
关键词 Supercritical Carbon Dioxide (sCO2) closed Brayton Cycle TECHNO-ECONOMICS Simulation Capital Expenditure Gas Turbine THERMODYNAMIC Equipment Cost Optimization and Sensitivity
下载PDF
Design and Test of Closed Hydraulic Transmission System of 4WD High-clearance Wheeled Sprayer
7
作者 Hengfeng CHEN Xiaobo XU 《Plant Diseases and Pests》 2024年第3期14-20,共7页
In conjunction with the working characteristics of the high-clearance wheeled sprayer and the benefits of the closed hydraulic system,a series of reasonable working parameters should be established,and a hydraulic sys... In conjunction with the working characteristics of the high-clearance wheeled sprayer and the benefits of the closed hydraulic system,a series of reasonable working parameters should be established,and a hydraulic system that fulfills the requisite specifications should be designed.The AMESim software model is employed to construct a closed hydraulic transmission system,and the simulation analysis is then performed according to the data of hydraulic components.According to analysis results,the prototype can be optimized and upgraded,and a verification test is further carried out.The test results demonstrate that the designed closed hydraulic transmission system meets the actual working requirements of the high-clearance wheeled sprayer and provides a stable experimental platform for intelligent control of agricultural machinery. 展开更多
关键词 closed hydraulic transmission system High-clearance Wheeled sprayer Modeling and simulation Verification test
下载PDF
Effect of periodic wide atmospheric pressure change on CO emission in closed goaf
8
作者 Zhuangzhuang Shao Bo Tan +6 位作者 Ruili Hu Xiaozhen Song Yan Guo Tianze Li Shuhui Fu Chaohuan Chen Haiyan Wang 《International Journal of Coal Science & Technology》 EI CAS CSCD 2023年第4期139-150,共12页
Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas ... Atmospheric pressure fuctuation is one of the most important factors afecting the climate environment and gas emission in the fre area.To obtain the infuence rule of the surface atmospheric pressure change on the gas sampling and abnormal emission in the mine closed goaf,the No.1 coal mine in Dananhu was taken as the research object.Using Fourier transform and Fisher harmonic analysis and other statistical methods,the infuence of the periodic variation of atmospheric pressure on the gas leakage and outfow in the closed goaf was studied.The results showed that there were three atmospheric pressure periods of 15.2 d,1 d and 182.2 d,and the probability was greater than 95%.The time period with the highest number of atmospheric pressure peaks was 7:00–8:00,which accounted for 20.2%of total occurrence number in a day.And the time periods with the highest number of atmospheric pressure trough were 2:00,15:00 and 16:00,accounting for 27.4%.The peak-to-trough transition time was mainly concentrated around 6 h,and the diurnal variation curve of atmospheric pressure was mainly bimodal.The atmospheric pressure change rate was mostly concentrated in 10–50 Pa/h.It was determined that the distance that the gas sampling pipe was pre-laid into the inner side of the closed wall should be greater than 44.4 m,and the CO concentration and atmospheric pressure in the closed goaf were both periodic and negative with atmospheric pressure.The research results have important guiding signifcance for the monitoring,early warning and environmental protection of the goaf. 展开更多
关键词 Atmospheric pressure Periodic variation closed goaf CO emission Coal mine
下载PDF
Performance analyses of two-phase closed thermosyphons for road embankments in the high-latitude permafrost regions
9
作者 WANG Guan-fu LIN Chuang +3 位作者 ZHU Long FENG De-cheng XIN Yang-yang ZHANG Feng 《Journal of Mountain Science》 SCIE CSCD 2023年第11期3138-3153,共16页
Two-phase closed thermosyphons(TPCTs)are widely used in infrastructure constructions in permafrost regions.Due to different climatic conditions,the effectiveness of TPCT will also be different,especially in the extrem... Two-phase closed thermosyphons(TPCTs)are widely used in infrastructure constructions in permafrost regions.Due to different climatic conditions,the effectiveness of TPCT will also be different,especially in the extremely cold region of the Da Xing'anling Mountains.In this study,a series of three-dimensional finite element TPCT embankment models were established based on the ZhanglingMohe highway TPCT test section in Da Xing'anling Mountains,and the thermal characteristics and the cooling effect of the TPCTs were analyzed.The results indicated that the TPCTs installed in the northeastern high-latitude regions is effective in cooling and stabilizing the embankment.The working cycle of the TPCTs is nearly 7 months,and the cooling range of the TPCTs can reach 3 m in this region.However,due to the extremely low temperature,the TPCT generates a large radial gradient in the permafrost layer.Meanwhile,by changing the climate conditions,the same type of TPCT embankment located in the Da Xing'anling Mountains,the Xiao Xing'anling Mountains,and the Qinghai-Tibet Plateau permafrost regions were simulated.Based on the comparison of the climate differences between the Qinghai-Tibet Plateau and Northeast China,the differences in the effectiveness of TPCTs were studied.Finally,the limitations of using existing TPCTs in high-latitude permafrost regions of China were discussed and the potential improvements of the TPCT in cold regions were presented. 展开更多
关键词 PERMAFROST Highway embankment Two-phase closed thermosyphon Numerical simulation Climatic condition Cooling performance
下载PDF
Closed corner divertor with B×▽B away from the divertor:a promising divertor scenario for tokamak power exhaust
10
作者 徐国盛 贾国章 +5 位作者 丁根凡 陶余强 孟令义 余林 王亮 刘建斌 《Plasma Science and Technology》 SCIE EI CAS CSCD 2023年第10期60-67,共8页
A major challenge facing the steady-state operation of tokamak fusion reactors is to develop a viable divertor solution with order-of-magnitude increase in power handling capability as compared with present experience... A major challenge facing the steady-state operation of tokamak fusion reactors is to develop a viable divertor solution with order-of-magnitude increase in power handling capability as compared with present experience.A recently developed divertor concept for this end has been tested recently on EAST tokamak through combining the effects of a closed divertor corner and E×B drifts.The E×B drifts in the divertor move particles towards the outer divertor corner area in the scrape-off layer for B×▽B directed away from the divertor,which can significantly enhance the particle concentration there,facilitating divertor detachment.In recent EAST experiments,the effects have been demonstrated where the lowest electron temperature at the divertor plate is obtained with strike point located close to the corner in the horizontal target and with B×▽B away from the divertor.These experimental results are in reasonable agreement with SOLPS-ITER simulations including drift effects,suggesting that the new divertor concept potentially provides a promising divertor solution for long-pulse operations of future tokamak fusion reactors with much higher power fluxes. 展开更多
关键词 divertor concept closed divertor corner E×B drifts SOLPS-ITER simulation EAST tokamak
下载PDF
Parameter Design of Current Double Closed Loop for T-Type Three-Level Grid-Connected Inverter
11
作者 Tiankui Sun Mingming Shi +3 位作者 Xiaolong Xiao Ping He Yu Ji Zhiyuan Yuan 《Energy Engineering》 EI 2023年第7期1621-1636,共16页
To reduce current harmonics caused by switching frequency,T-type grid-connected inverter topology with LCL filter is adopted.In view of the disadvantages of the slow response speed of the traditional current control a... To reduce current harmonics caused by switching frequency,T-type grid-connected inverter topology with LCL filter is adopted.In view of the disadvantages of the slow response speed of the traditional current control and the failure to eliminate the influence of the LCL filter on the grid-connected current by using current PI control alone,a current double closed loop PI current tracking control is proposed.Through the theoretical analysis of the grid-connected inverter control principle,the grid-connected inverter control model is designed,and the transfer functionmodel of each control link is deduced,and the current loop PI regulator is designed at last.The simulation results show that the control strategy is feasible. 展开更多
关键词 T-type inverter active damping current double closed loop
下载PDF
Meta-analysis of the efficacy of volar plate internal fixation versus closed reduction and external fixation in the treatment of adult distal radius fractures
12
作者 CHEN Jian-ge ZHANG Hai-ning +4 位作者 ZHAO Hong-zhou LIU Ming-jun XING Jia-hui WANG Ping WANG Wei-min 《Journal of Hainan Medical University》 CAS 2023年第19期44-56,共13页
Objective:To compare the efficacy of open reduction and volar locking plate internal fixation with closed reduction and external fixation in the treatment of distal radius fractures by using meta analysis.Methods:The ... Objective:To compare the efficacy of open reduction and volar locking plate internal fixation with closed reduction and external fixation in the treatment of distal radius fractures by using meta analysis.Methods:The databases of CNKI,Wanfang,Weipu,Chinese biomedical literature,Pubmed,Embase,and Cochrane Library were retrieved,and the randomized controlled studies that directly compared the efficacy of plate internal fixation and closed reduction external fixation in the treatment of distal radius fractures published publicly from the establishment of the database to April 2023 were collected.The two researchers independently screened the retrieved literature according to the inclusion and exclusion criteria,extracted data,used Cochrane risk bias assessment tool for quality assessment,and used RevMan 5.4 software for meta analysis.Results:A total of 10 randomized controlled trials were included,all of which were in English.There were 1042 patients in total,and 9 of them were rated as low risk.Meta analysis results showed that one year after the treatment of distal radius fracture with volar locking plate internal fixation,DASH score[MD=-5.64,95%CI(-7.21,-4.06),P<0.00001];One year later,PRWE score[MD=-5.90,95%CI(-8.88,-2.92),P=0.001];Palm flexion[MD=5.92,95%CI(1.29,10.55),P=0.01];Pronation[MD=2.48,95%CI(0.59,4.36),P=0.01];Postrotation[MD=4.73,95%CI(2.15,7.31),P=0.0003];Grip strength[MD=0.61,95%CI(0.12,1.10),P=0.02];palmar tilt angle[MD=9.84,95%CI(5.66,14.02),P<0.00001];Radial inclination[MD=4.33,95%CI(2.97,5.69),P<0.00001]was superior to closed reduction plaster or splint external fixation.One year later,the European Five dimensional Health Scale(EQ-5D-5L)score[MD=0.02,95%CI(-0.01,0.05),P=0.27];Back extension[MD=2.22,95%CI(-4.15,8.59),P=0.49];Ulnar deviation[MD=3.49,95%CI(-0.80,7.78),P=0.11];Radial deviation[MD=2.05,95%CI(-2.39,6.50),P=0.37];Ulnar variance[MD=-1.14,95%CI(-3.16,0.88),P=0.27];There was no significant difference in complications[MD=0.77,95%CI(0.54,1.10),P=0.16](P>0.05).Conclusion:Based on the current clinical data,internal fixation with volar locking plate is more conducive to mid-term DASH score and grip strength recovery than closed reduction plaster or splint external fixation,but there is no significant difference in the quality of life and complications of patients.For adult distal radius fractures,surgical indications should be carefully grasped,and non operative treatment should be given priority. 展开更多
关键词 Volar plate Internal fixation closed reduction External fixation PLASTER SPLINT Distal radius fracture Meta analysis
下载PDF
Design and analysis of an advanced thermal management system for the solar close observations and proximity experiments spacecraft 被引量:1
13
作者 Liu Liu Kangli Bao +4 位作者 Jianchao Feng Xiaofei Zhu Haoyu Wang Xiaofeng Zhang Jun Lin 《Astronomical Techniques and Instruments》 CSCD 2024年第1期52-61,共10页
In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relat... In this paper,the mission and the thermal environment of the Solar Close Observations and Proximity Experiments(SCOPE)spacecraft are analyzed,and an advanced thermal management system(ATMS)is designed for it.The relationship and functions of the integrated database,the intelligent thermal control system and the efficient liquid cooling system in the ATMS are elaborated upon.For the complex thermal field regulation system and extreme space thermal environment,a modular simulation and thermal field planning method are proposed,and the feasibility of the planning algorithm is verified by numerical simulation.A solar array liquid cooling system is developed,and the system simulation results indicate that the temperatures of the solar arrays meet the requirements as the spacecraft flies by perihelion and aphelion.The advanced thermal management study supports the development of the SCOPE program and provides a reference for the thermal management in other deep-space exploration programs. 展开更多
关键词 Solar close Observations and Proximity Experiments Adaptive thermal control method Thermal field planning method Pumped liquid cooling system Advanced thermal management system
下载PDF
Factors Associated with Closely Spaced Pregnancies at the Departmental Hospital Centre of Zou-Collines (Benin) in 2022
14
作者 Klikpezo Roger Hounkponou Nouéssewa Fanny Maryline +7 位作者 Atade Sèdjro Raoul Agbegbanou Eudoxie Ahouingnan Yeyinou Salifou Badaryatou Dettin Eric Obossou Achilles Imorou Sidi Salifou Kabibou 《Open Journal of Obstetrics and Gynecology》 2024年第1期89-101,共13页
Introduction: Birth spacing to prevent closely-spaced pregnancies, which are a source of maternal and neonatal morbidity and mortality, is not always respected by our women, as recommended by the World Health Organiza... Introduction: Birth spacing to prevent closely-spaced pregnancies, which are a source of maternal and neonatal morbidity and mortality, is not always respected by our women, as recommended by the World Health Organization (WHO). The objective was to study the factors associated with closely-spaced pregnancies among women followed at the Departmental Hospital Center du Zou et du Colline (DHC/Z-C) in 2022. Study Method: This was a descriptive, analytical cross-sectional study with prospective data collection from 20 May to 30 June 2022. Results: At the end of the study, 83 of the 117 women surveyed had close pregnancies, a frequency of 70.94%. They had an average age of 27.0 ± 6.3 years and were of Fon ethnicity and related in 91.57% of cases. The majority were married (96.60%). The factors significantly associated with these closely spaced pregnancies were age between 25 and 30 years, household occupation, age at first birth, age at marriage, women’s perception of contraceptive method (CM), women’s knowledge of the existence of a center providing family planning services and non-use of MC. Conclusion: Close pregnancies are still very common in the commune of Abomey. It is therefore important to increase the use of contraceptive methods in this part of the country. 展开更多
关键词 close Pregnancy Associated Factors DHC/Z-C
下载PDF
Formation of a Rapidly Rotating Classical Be-star in a Massive Close Binary System
15
作者 Evgeny Staritsin 《Research in Astronomy and Astrophysics》 SCIE CAS CSCD 2024年第1期44-50,共7页
This paper investigates the spin-up of a mass-accreting star in a close binary system passing through the first stage of mass exchange in the Hertzsprung gap. Inside an accreting star, angular momentum is carried by m... This paper investigates the spin-up of a mass-accreting star in a close binary system passing through the first stage of mass exchange in the Hertzsprung gap. Inside an accreting star, angular momentum is carried by meridional circulation and shear turbulence. The circulation carries part of the angular momentum of the accreted layers to the accretor's surface. The greater the rate of arrival of angular momentum in the accretor is, the greater this part. It is assumed that this part of the angular momentum can be removed by the disk further from the accretor. If the angular momentum in the matter entering the accretor is more than half the Keplerian value, then the angular momentum obtained by the accretor during mass exchange stage does not depend on the rate of arrival of angular momentum. The accretor may have the characteristics of a Be-star immediately after the end of mass exchange. 展开更多
关键词 (stars:)binaries(including multiple):close stars:emission-line BE stars:early-type stars:rotation
下载PDF
Closed-Loop System Identification Approach of the Inertial Models
16
作者 Irina Cojuhari 《Applied Mathematics》 2023年第2期107-120,共14页
The mathematical model that approximates the dynamics of the industrial process is essential for the efficient synthesis of control algorithms in industrial applications. The model of the process can be obtained accor... The mathematical model that approximates the dynamics of the industrial process is essential for the efficient synthesis of control algorithms in industrial applications. The model of the process can be obtained according to the identification procedures in the open-loop, or in the closed-loop. In the open-loop, the identification methods are well known and offer good process approximation, which is not valid for the closed-loop identification, when the system provides the feedback output and doesn’t permit it to be identified in the open-loop. This paper offers an approach for experimental identification in the closed-loop, which supposes the approximation of the process with inertial models, with or without time delay and astatism. The coefficients are calculated based on the values of the critical transfer coefficient and period of the underdamped response of the closed-loop system with P controller, when system achieves the limit of stability. Finally, the closed-loop identification was verified by the computer simulation and the obtained results demonstrated, that the identification procedure in the closed-loop offers good results in process of estimation of the model of the process. 展开更多
关键词 closed-Loop Identification Mathematical Modelling Inertial Models Time Delay Astatism
下载PDF
Study on the Effect of Behavioral Interventions Based on the Theory of“Knowledge,Attitude,Practice”on Tuberculosis Cognitive Level of Close Contacts
17
作者 Beiyan Zhang Yifei Hu +2 位作者 Jun Ji Donghui Hao Xuehui Jiao 《Journal of Clinical and Nursing Research》 2024年第2期123-128,共6页
Objective:Based on the theory of“Knowledge,Attitude,Practice,”health education was carried out for close contact with tuberculosis(TB)at a university in Beijing,and its impact on the students’awareness of TB was st... Objective:Based on the theory of“Knowledge,Attitude,Practice,”health education was carried out for close contact with tuberculosis(TB)at a university in Beijing,and its impact on the students’awareness of TB was studied.This study could provide a reference for effective health education interventions among close contacts of TB in undergraduates.Methods:102 undergraduates who had close contact with one confirmed case of pulmonary TB in April 2021 at a university were randomly divided into a control group and an intervention group.The intervention group was given the“Knowledge,Attitude,Practice”health education intervention by professionally trained doctors,and were asked to complete a self-designed TB-related questionnaire before and after the intervention.Both groups performed the Tuberculin Skin Test(TST)and chest X-ray(CR)examination.Results:The rate of the TST test was 18.6%,and CR examination showed 0 cases of pulmonary TB.The survey results showed that the TB awareness rate(96.1%,49/51)in the intervention group was significantly higher than that of the control group(51.0%,26/51),and the differences in awareness rate between the two groups were statistically significant(P<0.05).Regarding the attitude/skills toward TB,the prevalence rate of tuberculosis-related attitude/behavior in the intervention group(94.1%,47/51)was significantly higher than that of the control group(60.8%,31/51),and the differences between the two groups were statistically significant(P<0.05).Conclusion:Both self-controlled and parallel-controlled studies showed that the health education intervention of“Knowledge,Attitude,Practice”improved the awareness of TB among close contacts of TB in undergraduates. 展开更多
关键词 UNDERGRADUATES close contact of tuberculosis Behavioral intervention Health education
下载PDF
OPEN表和CLOSED表的合一 被引量:2
18
作者 冯乃勤 王岁花 +1 位作者 郑延斌 冯国燚 《计算机工程与应用》 CSCD 北大核心 2003年第16期100-101,125,共3页
在人工智能传统的搜索方法中,一直是将OPEN表和CLOSED表分开的。这不仅增加了搜索算法的复杂性,久而久之,也许禁锢了人们的思想。文章试图改变这种状况,提出了一种与众不同的新思路,巧妙地将OPEN表和CLOSED表合二为一,减少了一些工作量... 在人工智能传统的搜索方法中,一直是将OPEN表和CLOSED表分开的。这不仅增加了搜索算法的复杂性,久而久之,也许禁锢了人们的思想。文章试图改变这种状况,提出了一种与众不同的新思路,巧妙地将OPEN表和CLOSED表合二为一,减少了一些工作量,在一定程度上降低了算法的复杂性。 展开更多
关键词 搜索 0PEN表 closed 算法复杂性
下载PDF
Singular Points, Closed Orbits, Stable Manifolds and Unstable Manifolds of Second Order Autonomous Birkhoff Systems 被引量:1
19
作者 陈向炜 梅凤翔 《Journal of Beijing Institute of Technology》 EI CAS 1998年第4期330-336,共7页
Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and ... Aim To study singular points, closed orbits, stable manifolds and unstable manifolds of a second order autonomous Birkhoff system. Methods Qualitative methods of ordinary differential equation were used. Results and Conclusion The criteria for singular points, closed orbits and hyperbolic equilibrium points of a second order autonomous Birkhoff system are given. Moreover the stability of equilibria, stable manifolds and unstable manifolds are obtained. 展开更多
关键词 Birkhoff system singular point closed orbit stable manifold unstable manifold
下载PDF
New algorithm of mining frequent closed itemsets
20
作者 张亮 任永功 付玉 《Journal of Southeast University(English Edition)》 EI CAS 2008年第3期335-338,共4页
A new algorithm based on an FC-tree (frequent closed pattern tree) and a max-FCIA (maximal frequent closed itemsets algorithm) is presented, which is used to mine the frequent closed itemsets for solving memory an... A new algorithm based on an FC-tree (frequent closed pattern tree) and a max-FCIA (maximal frequent closed itemsets algorithm) is presented, which is used to mine the frequent closed itemsets for solving memory and time consuming problems. This algorithm maps the transaction database by using a Hash table,gets the support of all frequent itemsets through operating the Hash table and forms a lexicographic subset tree including the frequent itemsets.Efficient pruning methods are used to get the FC-tree including all the minimum frequent closed itemsets through processing the lexicographic subset tree.Finally,frequent closed itemsets are generated from minimum frequent closed itemsets.The experimental results show that the mapping transaction database is introduced in the algorithm to reduce time consumption and to improve the efficiency of the program.Furthermore,the effective pruning strategy restrains the number of candidates,which saves space.The results show that the algorithm is effective. 展开更多
关键词 frequent itemsets frequent closed itemsets minimum frequent closed itemsets maximal frequent closed itemsets frequent closed pattern tree
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部