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Analysis and Online Diagnosis on Plugging Fault of Servo Valve in Electro-hydraulic Regulating System of Steam Turbine 被引量:6
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作者 WANG Xuanyin LI Xiaoxiao LI Fushang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2009年第2期233-237,共5页
Through the study on the output signals of the electro-hydraulic regulating system in the thermal power plant, a novel method for online diagnosis of the plugging fault in the servo valve is presented. With the use of... Through the study on the output signals of the electro-hydraulic regulating system in the thermal power plant, a novel method for online diagnosis of the plugging fault in the servo valve is presented. With the use of the AMESIM software, the changes of the piston displacement, the oil pressure, the magnitude attenuation and the phase lag of the system under different plugging states are studied after simulation. Besides, the influences of the symmetrical and unsymmetrical plugging on the system are also compared and the characteristic table is given. The duo-neural network is put forward to achieve an online diagnosis on the plugging fault of the servo valve. The first level of network helps to make the qualitative diagnosis of the plugging position while the second level is for the quantitative diagnosis of the degree of the plugged position. The research results show that plugging at different positions exerts different influences on the performance of the system. The unsymmetrical plugging mainly affects the regulation time while the symmetrical plugging leads to great changes in the magnitude attenuation and the phase lag. 展开更多
关键词 steam turbine regulating system plugging diagnosis AMESIM software
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New advances of adiponectin in regulating obesity and related metabolic syndromes
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作者 Yanqi Han Qianwen Sun +7 位作者 Wei Chen Yue Gao Jun Ye Yanmin Chen Tingting Wang Lili Gao Yuling Liu Yanfang Yang 《Journal of Pharmaceutical Analysis》 SCIE CAS CSCD 2024年第5期623-638,共16页
Obesity and related metabolic syndromes have been recognized as important disease risks,in which the role of adipokines cannot be ignored.Adiponectin(ADP)is one of the key adipokines with various beneficial effects,in... Obesity and related metabolic syndromes have been recognized as important disease risks,in which the role of adipokines cannot be ignored.Adiponectin(ADP)is one of the key adipokines with various beneficial effects,including improving glucose and lipid metabolism,enhancing insulin sensitivity,reducing oxidative stress and inflammation,promoting ceramides degradation,and stimulating adipose tissue vascularity.Based on those,it can serve as a positive regulator in many metabolic syndromes,such as type 2 diabetes(T2D),cardiovascular diseases,non-alcoholic fatty liver disease(NAFLD),sarcopenia,neurodegenerative diseases,and certain cancers.Therefore,a promising therapeutic approach for treating various metabolic diseases may involve elevating ADP levels or activating ADP receptors.The modulation of ADP genes,multimerization,and secretion covers the main processes of ADP generation,providing a comprehensive orientation for the development of more appropriate therapeutic strategies.In order to have a deeper understanding of ADP,this paper will provide an all-encompassing review of ADP. 展开更多
关键词 ADIPONECTIN OBESITY Metabolic syndrome regulATION
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Controllable large-scale processing of temperature regulating sheath-core fibers with high-enthalpy for thermal management
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作者 Ziye Chen Zexu Hu +4 位作者 Shining Chen Senlong Yu Liping Zhu Hengxue Xiang Meifang Zhu 《Nano Materials Science》 EI CAS CSCD 2024年第3期337-344,共8页
Temperature regulating fibers(TRF_(s)) with high enthalpy and high form stability are the key factors for thermal management. However, the enthalpies of most TRFsare not high, and the preparation methods are still at ... Temperature regulating fibers(TRF_(s)) with high enthalpy and high form stability are the key factors for thermal management. However, the enthalpies of most TRFsare not high, and the preparation methods are still at the laboratory scale. It remains a great challenge to use industrial spinning equipment to achieve continuous processing of TRF_(s) with excellent thermal and mechanical properties. Here, polyamide 6(PA6) based TRF_(s) with a sheath-core structure were prepared by bicomponent melt-spinning. The sheath-core TRF(TRF_(sc)) are composed of PA6 as sheath and functional PA6 as core, which are filled with the shape stable phase change materials(ssPCM),dendritic silica@polyethylene glycol(SiO_(2)@PEG). With the aid of the sheath structure, the filling content of SiO_(2)@PEG can reach 30 %, so that the enthalpy of the TRF_(s) can be as high as 21.3 J/g. The ultra-high enthalpy guarantees the temperature regulation ability during the alternating process of cooling and heating. In hot environment, the temperature regulation time is 6.59 min, and the temperature difference is 12.93℃. In addition, the mechanical strength of the prepared TRF_(sc) reaches 2.26 cN/dtex, which can fully meet its application in the field of thermal management textiles and devices to manage the temperature regulation of the human body or precision equipment, etc. 展开更多
关键词 Thermal management Hybrid fibers Polyamides Bicomponent melt spinning Temperature regulating fibers
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Sirtuin 1 in regulating the p53/glutathione peroxidase 4/gasdermin D axis in acute liver failure
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作者 Swati Katoch Vikram Patial 《World Journal of Gastroenterology》 SCIE CAS 2024年第34期3850-3855,共6页
In this editorial,we comment on the article by Zhou et al.The study reveals the connection between ferroptosis and pyroptosis and the effect of silent information regulator sirtuin 1(SIRT1)activation in acute liver fa... In this editorial,we comment on the article by Zhou et al.The study reveals the connection between ferroptosis and pyroptosis and the effect of silent information regulator sirtuin 1(SIRT1)activation in acute liver failure(ALF).ALF is characterized by a sudden and severe liver injury resulting in significant hepatocyte damage,often posing a high risk of mortality.The predominant form of hepatic cell death in ALF involves apoptosis,ferroptosis,autophagy,pyroptosis,and necroptosis.Glutathione peroxidase 4(GPX4)inhibition sensitizes the cell to ferroptosis and triggers cell death,while Gasdermin D(GSDMD)is a mediator of pyroptosis.The study showed that ferroptosis and pyroptosis in ALF are regulated by blocking the p53/GPX4/GSDMD pathway,bridging the gap between the two processes.The inhibition of p53 elevates the levels of GPX4,reducing the levels of inflammatory and liver injury markers,ferroptotic events,and GSDMDN protein levels.Reduced p53 expression and increased GPX4 on deletion of GSDMD indicated ferroptosis and pyroptosis interaction.SIRT1 is a NAD-dependent deacetylase,and its activation attenuates liver injury and inflammation,accompanied by reduced ferroptosis and pyroptosis-related proteins in ALF.SIRT1 activation also inhibits the p53/GPX4/GSDMD axis by inducing p53 acetylation,attenuating LPS/D-GalN-induced ALF. 展开更多
关键词 Acute liver failure Ferroptosis Gasdermin D PYROPTOSIS P53 Silent information regulator sirtuin 1
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Correlation Between Granulomatous Mastitis and Autoimmune Function and the Immuneregulating Role of Traditional Chinese Medicine
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作者 Jiangshan Yuan Xufeng Cheng +1 位作者 Beibei Wang Zepeng Wang 《Chinese Medicine and Natural Products》 CAS 2024年第3期88-92,共5页
Granulomatous mastitis(GM)is a benign granulomatous condition,and its pathogenesis may be related to autoimmune disorders.Cellular immunity,humoral immunity,immunoglobulins,and complement could all play a role in the ... Granulomatous mastitis(GM)is a benign granulomatous condition,and its pathogenesis may be related to autoimmune disorders.Cellular immunity,humoral immunity,immunoglobulins,and complement could all play a role in the disease process,showing certain clinical patterns.Corticosteroids can quickly control disease progression,and immunosuppressants can be used for complex and refractory GM cases.In traditional Chinese medicine(TCM),“healthy qi”is similar to immune system function.For GM with deficient healthy qi,TCM treatments such as internal and external herbal applications can help regulate immune function and shorten disease duration by staged and TCM treatment,regulating viscera,reinforcing healthy qi,and eliminating pathogenic factors. 展开更多
关键词 GRANULOMATOUS MASTITIS TCM immune regulation TCM treatment staged treatment
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Regulating^(*)COOH intermediate via amino alkylation engineering for exceptionally effective photocatalytic CO_(2) reduction
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作者 Chengcheng Chen Qiaoyu Zhang +3 位作者 Fangting Liu Zhengguo Zhang Qiong Liu Xiaoming Fang 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第5期282-291,共10页
Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate ... Photocatalytic reduction of CO_(2) into fuel represents a promising approach for achieving carbon neutrality,while realizing high selectivity in this process is challenging due to uncontrollable reaction intermediate and retarded desorption of target products.Engineering the interface microenvironment of catalysts has been proposed as a strategy to exert a significant influence on reaction outcomes,yet it remains a significant challenge.In this study,amino alkylation was successfully integrated into the melem unit of polymeric carbon nitrides(PCN),which could efficiently drive the photocatalytic CO_(2) reduction.Experimental characterization and theoretical calculations revealed that the introduction of amino alkylation lowers the energy barrier for CO_(2) reduction into^(*)COOH intermediate,transforming the adsorption of^(*)COOH intermediate from the endothermic to an exothermic process.Notably,the as-prepared materials demonstrated outstanding performance in photocatalytic CO_(2) reduction,yielding CO_(2)at a rate of 152.8μmol h^(-1) with a high selectivity of 95.4%and a quantum efficiency of 6.6%. 展开更多
关键词 Polymeric carbonnitride regulate intermediate Photocatalytic CO_(2)reduction Amino alkylation ^(*)COOH adsorption
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Dynamic plugging regulating strategy of pipeline robot based on reinforcement learning
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作者 Xing-Yuan Miao Hong Zhao 《Petroleum Science》 SCIE EI CAS CSCD 2024年第1期597-608,共12页
Pipeline isolation plugging robot (PIPR) is an important tool in pipeline maintenance operation. During the plugging process, the violent vibration will occur by the flow field, which can cause serious damage to the p... Pipeline isolation plugging robot (PIPR) is an important tool in pipeline maintenance operation. During the plugging process, the violent vibration will occur by the flow field, which can cause serious damage to the pipeline and PIPR. In this paper, we propose a dynamic regulating strategy to reduce the plugging-induced vibration by regulating the spoiler angle and plugging velocity. Firstly, the dynamic plugging simulation and experiment are performed to study the flow field changes during dynamic plugging. And the pressure difference is proposed to evaluate the degree of flow field vibration. Secondly, the mathematical models of pressure difference with plugging states and spoiler angles are established based on the extreme learning machine (ELM) optimized by improved sparrow search algorithm (ISSA). Finally, a modified Q-learning algorithm based on simulated annealing is applied to determine the optimal strategy for the spoiler angle and plugging velocity in real time. The results show that the proposed method can reduce the plugging-induced vibration by 19.9% and 32.7% on average, compared with single-regulating methods. This study can effectively ensure the stability of the plugging process. 展开更多
关键词 Pipeline isolation plugging robot Plugging-induced vibration Dynamic regulating strategy Extreme learning machine Improved sparrow search algorithm Modified Q-learning algorithm
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Compartmentalized regulation of organelle integrity in neurodegenerative diseases:lessons from the Drosophila motor neuron
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作者 Hyun Sung 《Neural Regeneration Research》 SCIE CAS 2025年第1期195-196,共2页
Neurons are highly polarized,morphologically asymmetric,and functionally compartmentalized cells that contain long axons extending from the cell body.For this reason,their maintenance relies on spatiotemporal regulati... Neurons are highly polarized,morphologically asymmetric,and functionally compartmentalized cells that contain long axons extending from the cell body.For this reason,their maintenance relies on spatiotemporal regulation of organelle distribution between the somatodendritic and axonal domains.Although some organelles,such as mitochondria and smooth endoplasmic reticulum,are widely distributed throughout the neuron,others are segregated to either the somatodendritic or axonal compartment.For example,Golgi outposts and acidified lysosomes are predominantly present in the somatodendritic domain and rarely distributed along the axon,whereas newly formed autophagosomes and synaptic vesicles are mainly distributed in the distal axon(Britt et al.,2016). 展开更多
关键词 ORGANELLE regulATION DISTRIBUTION
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Pyroptosis,ferroptosis,and autophagy in spinal cord injury:regulatory mechanisms and therapeutic targets
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作者 Qingcong Zheng Du Wang +1 位作者 Rongjie Lin Weihong Xu 《Neural Regeneration Research》 SCIE CAS 2025年第10期2787-2806,共20页
Regulated cell death is a form of cell death that is actively controlled by biomolecules.Several studies have shown that regulated cell death plays a key role after spinal cord injury.Pyroptosis and ferroptosis are ne... Regulated cell death is a form of cell death that is actively controlled by biomolecules.Several studies have shown that regulated cell death plays a key role after spinal cord injury.Pyroptosis and ferroptosis are newly discovered types of regulated cell deaths that have been shown to exacerbate inflammation and lead to cell death in damaged spinal cords.Autophagy,a complex form of cell death that is interconnected with various regulated cell death mechanisms,has garnered significant attention in the study of spinal cord injury.This injury triggers not only cell death but also cellular survival responses.Multiple signaling pathways play pivotal roles in influencing the processes of both deterioration and repair in spinal cord injury by regulating pyroptosis,ferroptosis,and autophagy.Therefore,this review aims to comprehensively examine the mechanisms underlying regulated cell deaths,the signaling pathways that modulate these mechanisms,and the potential therapeutic targets for spinal cord injury.Our analysis suggests that targeting the common regulatory signaling pathways of different regulated cell deaths could be a promising strategy to promote cell survival and enhance the repair of spinal cord injury.Moreover,a holistic approach that incorporates multiple regulated cell deaths and their regulatory pathways presents a promising multi-target therapeutic strategy for the management of spinal cord injury. 展开更多
关键词 AUTOPHAGY cell death ferroptosis INFLAMMATION pathological mechanisms PYROPTOSIS regulated cell death regulatory pathways spinal cord injury therapeutic targets
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Regulator of G protein signaling 6 mediates exercise-induced recovery of hippocampal neurogenesis,learning,and memory in a mouse model of Alzheimer’s disease
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作者 Mackenzie M.Spicer Jianqi Yang +5 位作者 Daniel Fu Alison N.DeVore Marisol Lauffer Nilufer S.Atasoy Deniz Atasoy Rory A.Fisher 《Neural Regeneration Research》 SCIE CAS 2025年第10期2969-2981,共13页
Hippocampal neuronal loss causes cognitive dysfunction in Alzheimer’s disease.Adult hippocampal neurogenesis is reduced in patients with Alzheimer’s disease.Exercise stimulates adult hippocampal neurogenesis in rode... Hippocampal neuronal loss causes cognitive dysfunction in Alzheimer’s disease.Adult hippocampal neurogenesis is reduced in patients with Alzheimer’s disease.Exercise stimulates adult hippocampal neurogenesis in rodents and improves memory and slows cognitive decline in patients with Alzheimer’s disease.However,the molecular pathways for exercise-induced adult hippocampal neurogenesis and improved cognition in Alzheimer’s disease are poorly understood.Recently,regulator of G protein signaling 6(RGS6)was identified as the mediator of voluntary running-induced adult hippocampal neurogenesis in mice.Here,we generated novel RGS6fl/fl;APP_(SWE) mice and used retroviral approaches to examine the impact of RGS6 deletion from dentate gyrus neuronal progenitor cells on voluntary running-induced adult hippocampal neurogenesis and cognition in an amyloid-based Alzheimer’s disease mouse model.We found that voluntary running in APP_(SWE) mice restored their hippocampal cognitive impairments to that of control mice.This cognitive rescue was abolished by RGS6 deletion in dentate gyrus neuronal progenitor cells,which also abolished running-mediated increases in adult hippocampal neurogenesis.Adult hippocampal neurogenesis was reduced in sedentary APP_(SWE) mice versus control mice,with basal adult hippocampal neurogenesis reduced by RGS6 deletion in dentate gyrus neural precursor cells.RGS6 was expressed in neurons within the dentate gyrus of patients with Alzheimer’s disease with significant loss of these RGS6-expressing neurons.Thus,RGS6 mediated voluntary running-induced rescue of impaired cognition and adult hippocampal neurogenesis in APP_(SWE) mice,identifying RGS6 in dentate gyrus neural precursor cells as a possible therapeutic target in Alzheimer’s disease. 展开更多
关键词 adult hippocampal neurogenesis Alzheimer’s disease dentate gyrus EXERCISE learning/memory neural precursor cells regulator of G protein signaling 6(RGS6)
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The Response of Different Drought-resistance of Wheat Varieties under Drought Stress and the Regulating Role of Nitric Oxygen 被引量:6
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作者 曲小菲 吕淑敏 +3 位作者 王林华 梁书荣 刘魏魏 赵会杰 《Agricultural Science & Technology》 CAS 2010年第4期30-33,63,共5页
[Objective]The aim was to study the response mechanism of drought stress of wheat varieties in different drought-resistance species,and protect the effect of exogenous NO on oxidative damage and photosynthetic apparat... [Objective]The aim was to study the response mechanism of drought stress of wheat varieties in different drought-resistance species,and protect the effect of exogenous NO on oxidative damage and photosynthetic apparatus of wheat leaves under drought stress.[Method]Using low-resistance Yumai 949 and high-resistance Xiamai 5 as test materials,drought stress was carried out to seedlings in five-leaf stage with 15% PEG-6000,and then NO(0.75 mmol/L SNP,sodium nitroprusside,exogenous NO donor) was used for regulation in drought condition,and antioxidant and photosynthetic activities was determined.Three treatments were set in the experiment.[Result]SOD,CAT and APX activities of high resistance Xiamai 5 were much higher than low resistance Yumai 949,so were MDA and chlorophyll content.And the change range of these physiological indexes of high resistance species was smaller than high-yielding and low resistance species under drought stress.NO increased the adaptation to drought stress of these physiological indexes significantly.[Conclusion]Exogenous NO could increase the activity of antioxidant enzymes of wheat leaves under drought stress,and enhance the drought resistance of wheat. 展开更多
关键词 WHEAT Drought stress NO regulATION
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Review on Effects of Application of Exogenous Growth Regulating Substance on Fruits Weight of Peach
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作者 马之胜 贾云云 +3 位作者 王越辉 白瑞霞 陈江玉 刘志欣 《Agricultural Science & Technology》 CAS 2015年第8期1681-1685,共5页
The effects of exogenous growth regulating substance on the fruit weight of peach were reviewed. Paclobutrazol could increase the single fruit weight in dif- ferent degree, and cytokinins could also increase the singl... The effects of exogenous growth regulating substance on the fruit weight of peach were reviewed. Paclobutrazol could increase the single fruit weight in dif- ferent degree, and cytokinins could also increase the single fruit weight. GA3 and B9 had no effect on fruit size or on reducing single fruit weight. Chlorflurenol-methy, ABT and salicylic acid had no effect on fruit size. Suggestions on the future re- search were put forward. 展开更多
关键词 PEACH Fruit size Yield Exogenous growth regulating substance
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Study on the Effect of Osmosis-regulating Substances and Organic Appendices on Somatic Embryogenesis in Wheat 被引量:4
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作者 孙朝霞 侯思宇 王玉国 《Agricultural Science & Technology》 CAS 2008年第3期46-48,共3页
[Objective] The study aimed to reveal the effect of osmosis-regulating substances and organic appendices on somatic embryogenesis in wheat. [Method] The suitable concentration combination of appendices was optimized b... [Objective] The study aimed to reveal the effect of osmosis-regulating substances and organic appendices on somatic embryogenesis in wheat. [Method] The suitable concentration combination of appendices was optimized by adding different concentrations of osmosis-regulating substances including mannitol, sorbitol and organic appendices such as Gln, CH and LH, into the somatic embryogenesis in wheat. [Result] The mannitol or sorbitol lower than 40 g/L was helpful for improving somatic embryogenesis; there was no significant difference in the induction rate of somatic embryogenesis when 300-500 mg/L Gln、CH or LH was respectively added into the induced medium, while somatic embryogenesis could be enhanced dramatically in the presence of 500 mg/L Gln together with 300 mg/L CH. [Conclusion] Somatic embryogenesis could be improved to some extent by different concentrations of osmosis-regulating substances and organic appendices, which laid foundation for establishing a more perfect system of somatic embryogenesis in wheat. 展开更多
关键词 WHEAT SOMATIC EMBRYOGENESIS ORGANIC appendix Osmosis-regulating substance
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PID Controller Optimization by GA and Its Performances on the Electro-hydraulic Servo Control System 被引量:22
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作者 Karam M. Elbayomy 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2008年第4期378-384,共7页
A proportional integral derivative (PID) controller is designed and attached to electro-hydraulic servo actuator system (EHSAS) to control the angular position of the rotary actuator which control the movable surf... A proportional integral derivative (PID) controller is designed and attached to electro-hydraulic servo actuator system (EHSAS) to control the angular position of the rotary actuator which control the movable surface of space vehicles. The PID gain parameters are optimized by the genetic algorithm (GA). The controller is verified on the new state-space model of servo-valves attached to the physical rotary actuator by SIMULINK program. The controller and the state-space model are verified experimentally. Simulation and experimental results verify the effectiveness of the PID controller adaptive by GA to control the angular position of the rotary actuator as compared with the classical PID controller and the compensator controller. 展开更多
关键词 PID controller electro-hydraulic servo control system genetic controller GA
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RESEARCH ON THE ENERGY ECONOMIZATION OF ELECTRO-HYDRAULIC HAMMER 被引量:10
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作者 Lei Bufang Li Yongtang Liu Jiansheng (Department of Mechanical Engineering, Taiyuan Heavy Machinery Institute) 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2000年第1期54-69,共6页
The research on the driving principle and economization of energy of electro-hydraulic hammer is discussed. By means of the balance chart of energy, the method and formulas to calculate every level efficiency and the ... The research on the driving principle and economization of energy of electro-hydraulic hammer is discussed. By means of the balance chart of energy, the method and formulas to calculate every level efficiency and the total efficiency of steam drived hammer are formed.With the aid of actual data of plants,the actual efficiency of steam drived hammer is got. The working principle and the driving system of electro-hydraulic hammer are introduced. The procedure of energy energy of this hammer is analyzed. The utilization ratio of energy of this type of hammer is got. It is shown that the efficiency of electro-hydraulic hammer is 7 times as much as that of steam drived hammer. 展开更多
关键词 Steam hammer electro-hydraulic hammer Economization
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YAP promotes osteogenesis and suppresses adipogenic differentiation by regulatingβ-catenin signaling 被引量:25
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作者 Jin-Xiu Pan Lei Xiong +10 位作者 Kai Zhao Peng Zeng Bo Wang Fu-Lei Tang Dong Sun Hao-han Guo Xiao Yang Shun Cui Wen-Fang Xia Lin Mei Wen-Cheng Xiong 《Bone Research》 CAS CSCD 2018年第2期155-166,共12页
YAP(yes-associated protein) is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone h... YAP(yes-associated protein) is a transcriptional factor that is negatively regulated by Hippo pathway, a conserved pathway for the development and size control of multiple organs. The exact function of YAP in bone homeostasis remains controversial. Here we provide evidence for YAP's function in promoting osteogenesis, suppressing adipogenesis, and thus maintaining bone homeostasis.YAP is selectively expressed in osteoblast(OB)-lineage cells. Conditionally knocking out Yap in the OB lineage in mice reduces cell proliferation and OB differentiation and increases adipocyte formation, resulting in a trabecular bone loss. Mechanistically, YAP interacts with β-catenin and is necessary for maintenance of nuclear β-catenin level and Wnt/β-catenin signaling. Expression of β-catenin in YAP-deficient BMSCs(bone marrow stromal cells) diminishes the osteogenesis deficit. These results thus identify YAP-β-catenin as an important pathway for osteogenesis during adult bone remodeling and uncover a mechanism underlying YAP regulation of bone homeostasis. 展开更多
关键词 OB YAP promotes osteogenesis suppresses adipogenic differentiation regulating catenin signaling BMSCs
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Output Waveform Analysis of an Electro-hydraulic Vibrator Controlled by the Multiple Valves 被引量:10
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作者 REN Yan RUAN Jian JIA Wen'ang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2014年第1期186-197,共12页
The existing research of the electro-hydraulic vibrator mainly focuses on system stability, working frequency width and output waveform distortion. However, this high frequency performance of the electro-hydraulic vib... The existing research of the electro-hydraulic vibrator mainly focuses on system stability, working frequency width and output waveform distortion. However, this high frequency performance of the electro-hydraulic vibrator is difficult to be improved greatly due to fast insufficiently frequency response of the servo valve itself and limited compensation capability of the control structure in the vibrator system. In this paper, to realize high frequency vibration, an improved two-dimensional valve (here within defined as a 2D valve) as a main control component is adopted to the parallel connection with a servo valve to control the electro-hydraulic vibrator, Because the output waveforms of this electro-hydraulic vibrator are incapable to be verified through timely feedback as in the conventional electro-hydraulic servo system, the analysis to the output waveform becomes crucial to the design and control of the electro-hydraulic vibrator. The mathematical models of hydraulic actuation mechanism and the orifice area of the parallel valves connection are established first. And then the vibration process is divided into two sections in terms of the direction of the flow, the analytical expression of the excited waveform is solved. Based on relationships exist between working states and the control parameters the analytical results, the vibration boundary positions and the are derived. Finally an experimental system was built to validate the theoretical analysis. It is verified that this electro-hydraulic vibration system could achieve high working frequency, up to 2 000 Hz. The excited waveform is similar to the sinnsoidal waveform. And the ascent and decent slopes of the waveforms are somewhat asymmetrical. This asymmetry is not only caused by the change of the direction of the elastic force but also dependent on the bias position of the vibration. Consequentky the distortion of effective working waveform is less tha~ 10%. This electro-hydraulic vibrator controlled by the multiple valves could not only greatly enhance the working frequency but also precisely control the vibration characteristic variables such as waveform shape. 展开更多
关键词 2D valves hydraulic multiple-valve system electro-hydraulic vibrator excited waveform
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Fuzzy iterative learning control of electro-hydraulic servo system for SRM direct-drive volume control hydraulic press 被引量:18
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作者 郑建明 赵升吨 魏树国 《Journal of Central South University》 SCIE EI CAS 2010年第2期316-322,共7页
A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM(switched reluctance motor) driving technology is developed.Considering that the serious dead zone and time-variant no... A new kind of volume control hydraulic press that combines the advantages of both hydraulic and SRM(switched reluctance motor) driving technology is developed.Considering that the serious dead zone and time-variant nonlinearity exist in the volume control electro-hydraulic servo system,the ILC(iterative learning control) method is applied to tracking the displacement curve of the hydraulic press slider.In order to improve the convergence speed and precision of ILC,a fuzzy ILC algorithm that utilizes the fuzzy strategy to adaptively adjust the iterative learning gains is put forward.The simulation and experimental researches are carried out to investigate the convergence speed and precision of the fuzzy ILC for hydraulic press slider position tracking.The results show that the fuzzy ILC can raise the iterative learning speed enormously,and realize the tracking control of slider displacement curve with rapid response speed and high control precision.In experiment,the maximum tracking error 0.02 V is achieved through 12 iterations only. 展开更多
关键词 hydraulic press volume control electro-hydraulic servo iterative learning control fuzzy control
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Separate Control of High Frequency Electro-hydraulic Vibration Exciter 被引量:7
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作者 JIA Wen'ang RUAN Jian REN Yan 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2011年第2期293-302,共10页
The working frequency of the conventional electro-hydraulic vibration exciters,which consist of a servo valve and a hydraulic cylinder,is generally restricted within a narrow range due to limited frequency response ca... The working frequency of the conventional electro-hydraulic vibration exciters,which consist of a servo valve and a hydraulic cylinder,is generally restricted within a narrow range due to limited frequency response capability of the servo valve itself.To counteract such restriction,a novel scheme for an electro-hydraulic vibrator,controlled by a two-dimensional valve(2D valve) and a bias valve in parallel,is therefore proposed.The frequency,amplitude and offset are independently controlled by rotary speed,axial sliding of the spool of the 2D valve and axial sliding of the spool of the bias valve.The principle of separate control was presented and the regulation approach of frequency,amplitude and offset was discussed.A mathematical model of the hydraulic power mechanism for the proposed vibration exciter was established to investigate the relationship between the amplitude and the axial sliding of the 2D valve' spool,as well as that between the offset and the axial sliding of the bias valve's spool at various frequencies.An experimental system was built to validate the theoretical analysis.It is verified that the 2D exciter is capable of working smoothly in a frequency range of 5- 200 Hz.And its frequency,amplitude and offset can be controlled respectively by either closed loop or open loop method.There is a linear relationship between the output amplitude and the spool axial opening of the 2D valve until a point when the flow rate becomes saturate and the amplitude remains constant.The offset displacement of the cylinder's piston is linearly proportional to the axial displacement of the spool of the bias valve,when the valve opening is less than 25%.Thereafter,the slop of the offset curve decreases and tends to saturate.The proposed electro-hydraulic vibration controlled by the 2D valve not only facilitates the realization of high-frequency electro-hydraulic vibration,the high-accuracy of vibration can also be achieved by means of independent controls to the frequency,amplitude and offset. 展开更多
关键词 control valves electro-hydraulic system vibration exciter dynamics characteristics
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New Method to Improve Dynamic Stiffness of Electro-hydraulic Servo Systems 被引量:9
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作者 BAI Yanhong QUAN Long 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2013年第5期997-1005,共9页
Most current researches working on improving stiffness focus on the application of control theories.But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so... Most current researches working on improving stiffness focus on the application of control theories.But controller in closed-loop hydraulic control system takes effect only after the controlled position is deviated,so the control action is lagged.Thus dynamic performance against force disturbance and dynamic load stiffness can’t be improved evidently by advanced control algorithms.In this paper,the elementary principle of maintaining piston position unchanged under sudden external force load change by charging additional oil is analyzed.On this basis,the conception of raising dynamic stiffness of electro hydraulic position servo system by flow feedforward compensation is put forward.And a scheme using double servo valves to realize flow feedforward compensation is presented,in which another fast response servo valve is added to the regular electro hydraulic servo system and specially utilized to compensate the compressed oil volume caused by load impact in time.The two valves are arranged in parallel to control the cylinder jointly.Furthermore,the model of flow compensation is derived,by which the product of the amplitude and width of the valve’s pulse command signal can be calculated.And determination rules of the amplitude and width of pulse signal are concluded by analysis and simulations.Using the proposed scheme,simulations and experiments at different positions with different force changes are conducted.The simulation and experimental results show that the system dynamic performance against load force impact is largely improved with decreased maximal dynamic position deviation and shortened settling time.That is,system dynamic load stiffness is evidently raised.This paper proposes a new method which can effectively improve the dynamic stiffness of electro-hydraulic servo systems. 展开更多
关键词 electro-hydraulic servo system flow feedforward compensation dynamic load stiffness double-valve actuation
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