BACKGROUND This study examines the complex relationships among the neuroendocrine axis,gut microbiome,inflammatory responses,and gastrointestinal symptoms in patients with irritable bowel syndrome(IBS).The findings pr...BACKGROUND This study examines the complex relationships among the neuroendocrine axis,gut microbiome,inflammatory responses,and gastrointestinal symptoms in patients with irritable bowel syndrome(IBS).The findings provide new insights into the pathophysiology of IBS and suggest potential therapeutic targets for improving patient outcomes.AIM To investigate the interactions between the neuroendocrine axis,gut microbiome,inflammation,and gastrointestinal symptoms in patients with IBS.METHODS Patients diagnosed with IBS between January 2022 and January 2023 were selected for the study.Healthy individuals undergoing routine check-ups during the same period served as the control group.Data were collected on neuroendocrine hormone levels,gut microbiome profiles,inflammatory biomarkers,and gastrointestinal symptomatology to analyze their interrelations and their potential roles in IBS pathogenesis.RESULTS IBS patients exhibited significant dysregulation of the neuroendocrine axis,with altered levels of cortisol,serotonin,and neuropeptides compared to healthy controls.The gut microbiome of IBS patients showed reduced diversity and specific alterations in bacterial genera,including Bifidobacterium,Lactobacillus,and Faecalibacterium,which were associated with neuroendocrine disturbances.Additionally,elevated levels of inflammatory markers,such as C-reactive protein,interleukin-6,and tumor necrosis factor-α,were observed and correlated with the severity of gastrointestinal symptoms like abdominal pain,bloating,and altered bowel habits.CONCLUSION The findings suggest that targeting the neuroendocrine axis,gut microbiome,and inflammatory pathways may offer novel therapeutic strategies to alleviate symptoms and improve the quality of life in IBS patients.展开更多
As a new ionic polymer-metal composite(IPMC) for artificial muscle,the mechanical performance parameters and the relationship between the deformation and the electrical parameters of the IPMC were studied. With the di...As a new ionic polymer-metal composite(IPMC) for artificial muscle,the mechanical performance parameters and the relationship between the deformation and the electrical parameters of the IPMC were studied. With the digital speckle correlation method,the constitutive relationship of the IPMC was confirmed. With non-contact photography measurement,a cantilever setup was designed to confirm the relationship between the deformation of the IPMC film and the applied voltage. The relationship curve of tip displacement of the IPMC cantilever setup vs the voltage was achieved. The results indicate that the IPMC is isotropic,its elastic modulus is 232 MPa and Poisson ratio is 0.163. The curve achieved from the test of the tip displacement of the IPMC cantilever setup shows that the tip displacement reaches the maximum when the stimulated voltage is 5 V. And the tip displacement descends largely when the frequency of the applied voltage is between 30 mHz and 100 mHz.展开更多
Conditions for complete and lag synchronizations in drive-response systems are considered under the unified framework of generalized synchronization. The question is addressed that whether the synchronization conditio...Conditions for complete and lag synchronizations in drive-response systems are considered under the unified framework of generalized synchronization. The question is addressed that whether the synchronization conditions achieving complete synchronization is still valid for lag synchronization when the time delay of signal transmission between the drive and response systems increases from 0. Theoretical and numerical results show that whether the synchronization conditions is stable for the influence of the time delay of signal transmission depends on a particular form of equilibria of the drive and response systems. Furthermore, it seems that the less the number of the equilibria of the drive system, the more likely the synchronization conditions are stable for the time delay of signal trans- mission.展开更多
Peninsular Malaysia is located and lies in a low seismic region. Although Malaysia is not located in the active fault seismic area, it is closed to the Sumatran active seismic zones. Tall building are fIequently felt ...Peninsular Malaysia is located and lies in a low seismic region. Although Malaysia is not located in the active fault seismic area, it is closed to the Sumatran active seismic zones. Tall building are fIequently felt the tremor generated fTom Sumatran subduction and fault zones especially in the west cost of Peninsular Malaysia such as Johor Bahru, Kuala Lumpur and Penang. Existing design response spectra was developed based on attenuation relationship for each subduction and fault zone. In this study, the design response spectra were developed based on various attenuation relationships for selected location in Kuala Lumpur area, namely, Mutiara Damansara, Bandar Petaling Jaya and Bandar Puteri Puchong. The development of design response spectra based on various attenuation relationships is more reliable in selecting the appropriate attenuation relationship for the study area. Seven attenuations have been chosen and results show that Megawati et al. are the most appropriate attenuation relation for fault zone, where the predicted PGA (peak ground acceleration) is 0.0187 g which is the proposed PGA value for this study area. This study also found that most of soil in the study area can be categorized into SD (stiff soil) according to site classification in the NEHRP 2000 Provision/UBC 97. Bandar petaling Jaya was found to be highest AF (amplification factor) of 3.74 for stiff soil and Mutiara Damansara with AF of 2.67 for very dense soil or soft rock. The proposed design response spectra for each location were developed based on UBC 1997 (Uniform Building Code 1997). The peak RSA (response spectrum acceleration) of 0.30 g for soil type SD for Bandar Petaling Jaya is the maximum level of acceleration on the soil surface with a period range of 0.10 to 0.52 seconds. All these values can be used for the seismic safety evaluation of existing structures and as a guideline in designing new structures to resist future earthquake, within the study area.展开更多
This paper describes the experimental study on shock response of FDB (fluid dynamic bearing) spindle for HDDs (hard disk drives). The FDBs are widely used as rotating shaft support elements for HDD spindle motors....This paper describes the experimental study on shock response of FDB (fluid dynamic bearing) spindle for HDDs (hard disk drives). The FDBs are widely used as rotating shaft support elements for HDD spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipment such as mobile PCs (personal computers), video cameras, car navigation systems and so on. Hence, the rotating shaft has a possibility to come in contact with the bearing by external shocks and it causes wear or seizure to the bearing surface. To avoid the problem, it is extremely important to know how the spindle moves against the large shock on HDDs experimentally. However, as far as the authors know, there are few experimental studies treating the shock response of HDD spindles. In this paper, firstly, we propose a new test rig and experimental method for shock response of FDB spindles. Then the shock tests against the radial and axial disturbance on FDB spindle for 2.5" HDD are conducted. Finally, the experimental results of shock response waveforms and maximum displacement of disk are shown.展开更多
This paper studies the generalized synchronization of a class of drive-response neural networks with time-varying delay. When the topological structures of the drive-response neural networks are known, by designing an...This paper studies the generalized synchronization of a class of drive-response neural networks with time-varying delay. When the topological structures of the drive-response neural networks are known, by designing an appropriate nonlinear adaptive controller, the generalized synchronization of these two networks is obtained based on Lyapunov stability theory and LaSalle’s invariance principle.展开更多
The sequence stratigraphy framework of Paleogene of Qikou Sag has been built in this paper. The evolution law of episodic subsidence in Qikou Sag has been expounded, with the analysis of the characteristic of sequence...The sequence stratigraphy framework of Paleogene of Qikou Sag has been built in this paper. The evolution law of episodic subsidence in Qikou Sag has been expounded, with the analysis of the characteristic of sequence thickness, as well as the study of consedimental tectonic activity, subsidence history, paleogeomorphology and the coupling relationship among them. The faults controlling action was the dominant mechanism during rifting stage I , as the depression was the dominant mechanism during rifting stage III, which embodies a process from intense disparity fault depression to integral subsidence. Meanwhile, under the control of regional faulting and later stage depression, subsidence rate centers and paleogeomorphic concave centers are always corresponding to the sequence thickness centers, and the changes of subsidence centers and paleogeomorphology concave centers are consistent with the migration of thickness centers, which presents the restriction, coupling and response among them and clarifies the law that tectonic activity controls the basin fill by means of controlling the subsidence rate and paleogeomorphology from contributing factor angle. On this basis, the dynamic evolution of the composite pattern of structure-subsidence-deposition in the fault controlling actic region during the three rifting stages and their petroleum geological significance has been discussed.展开更多
A convenient and universal residue calculus method is proposed to study the stochastic response behaviors of an axially moving viscoelastic beam with random noise excitations and fractional order constitutive relation...A convenient and universal residue calculus method is proposed to study the stochastic response behaviors of an axially moving viscoelastic beam with random noise excitations and fractional order constitutive relationship, where the random excitation can be decomposed as a nonstationary stochastic process, Mittag-Leffler internal noise, and external stationary noise excitation. Then, based on the Laplace transform approach, we derived the mean value function, variance function and covariance function through the Green's function technique and the residue calculus method, and obtained theoretical results. In some special case of fractional order derivative α , the Monte Carlo approach and error function results were applied to check the effectiveness of the analytical results, and good agreement was found. Finally in a general-purpose case, we also confirmed the analytical conclusion via the direct Monte Carlo simulation.展开更多
Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversit...Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversity. The river-lake relationship between Mekong River and Tonle Sap Lake is unique and has always been a major focus in the international community. The land terrain and under-water topography were used to analyze the morphological characteristics of Cambodia Mekong Delta and Tonle Sap Lake. Long series of hydrological data of river-lake controlling stations were used to analyze the water level variation characteristics and water volume exchange pattern between Mekong River and Tonle Sap Lake, and the response relationship to river-lake morphological characteristics were also researched. The results show that: Cambodia Mekong Delta and Tonle Sap Lake Area is low-lying and flat with gentle channel gradient and water surface gradient, making the relationship between water level and area (or volume) smooth. The channel storage capacity of Mekong River and Tonle Sap River is not enough compared to the inflow, so vast flooding plain is extremely prone to be inundated, making the flood relationships between the left and right banks become very complicated. Tonle Sap Lake is a seasonal freshwater lake with water flowing in and flowing out, and the timing and intensity of water exchange with Mekong River are closely related to the water flow resistance at the exit section of Tonle Sap Lake and the cross-sectional area of Tonle Sap River, which can be reflected by the river-lake water level difference and the water level of Tonle Sap River. Affected by the river-lake morphological characteristics, the water exchange intensity between Mekong River and Tonle Sap Lake is great. Tonle Sap Lake not only stores 14.4% of flood volume (39.7 billion m3) from the Mekong River every year, but also supplies 29.7% of dry water (69.4 billion m3) to the Mekong River. Influenced by the adjustment of the floodplain, the water level fluctuation of Mekong River and Tonle Sap Lake is slow, and the rising and droop rates of water level are positively correlated with the floodplain storage area. The research results will help to understand the relationship mechanism between Mekong River and Tonle Sap Lake and provide a scientific basis for the comprehensive governance of Cambodia Mekong Delta and Tonle Sap Lake Area.展开更多
Under the new normal economic growth, lack of motivation, structural imbalances in the economy, the shortage of resources, resource utilization inefficiency, environmental damage and other issues have become increasin...Under the new normal economic growth, lack of motivation, structural imbalances in the economy, the shortage of resources, resource utilization inefficiency, environmental damage and other issues have become increasingly prominent, enterprises as the carrier of economy is one of the root of the problem. Research on enterprise innovation and corporate social responsibility issues, it is conducive to the development of enterprise itself and the transformation of Chinese economy. This paper reviewed the research status of relationships between innovation and corporate social responsibility, through comb the aspects of the definitions and evolution of enterprise innovation and social responsibility, also include both the relationship and the new way(responsible innovation) of combination of them, we found the presence of index system is not perfect, and lack of in-depth comprehensive study and opportunities for future research is prospected.展开更多
The increasing use of diesel-powered equipment in confined spaces(underground mines) has the potential to over expose underground miners under the threat of diesel particulate matter(DPM). Miners in underground mines ...The increasing use of diesel-powered equipment in confined spaces(underground mines) has the potential to over expose underground miners under the threat of diesel particulate matter(DPM). Miners in underground mines can be exposed to DPM concentrations far more than works in other industries. A great number of animal and epidemiological studies have shown that both short-term and long-term DPM exposure have adverse health effect. Based on reviews of related studies, especially some recent evidence, this paper investigated the long and short-term health effects based on animal studies and epidemiological studies. The exposure-response relationship studies were also explored and compared to the current DPM regulation or standards in some countries. This paper found that the DPM health effect studies specifically for miners are not sufficient to draw solid conclusions, and a recommendation limit of DPM concentration can be put in place for better protection of miners from DPM health risk. Current animal studies lack the use of species that have similar lung functions as human for understanding the cancer mode of action in human. And finally, the DPM health hazard will continue to be a challenging topic before the mode of action and reliable exposure-response relationship are established.展开更多
The dose-response curves obtained by premature condensed chromosome (PCC)and conventional cellular genetic methods can be represented by two linear equations. The ratiO of the slopes, Kpcc/KM,, is about 28. In compari...The dose-response curves obtained by premature condensed chromosome (PCC)and conventional cellular genetic methods can be represented by two linear equations. The ratiO of the slopes, Kpcc/KM,, is about 28. In comparison to the conventional method, the PCC method has many advantages; e,g. it is faster, simpler, more sensitive and accurate. Its significance in the study of radiation damage is also discussed.展开更多
A harmonious relationship between teachers and postgraduates presents the comprehensive value of psychological education,which guarantees training quality and acts as an effective carrier of mental health education of...A harmonious relationship between teachers and postgraduates presents the comprehensive value of psychological education,which guarantees training quality and acts as an effective carrier of mental health education of the postgraduates.Based on Bandura’s theory of reciprocal determinism and Austin’s input-output theory,this paper constructs a model concerning the value of psychological education in the tutor-student relationship.The path of realization is also explored in a structural equation model through a questionnaire survey of 1112 graduate supervisors and administrators in medical colleges.The experimental result indicates that(1)The interaction between teachers and postgraduates promotes the value of psychological education in the highest measure,among which the quality and frequency of tutor-student communication,mutual trust,and respect act as the key influencing indicators.(2)Tutor’s professional quality is considered as the fundamental driving force in the realization of psychological education value in the tutor-student relationship,the maximum mediating effect is observed in the developing path of tutor’s professional quality-interaction behavior between teachers and postgraduates-psychological growth of teachers and postgraduates.(3)The objective results obtained by teachers and postgraduates,such as the improvement of quality and quantity,positively promote the overall quality of life satisfaction of both sides,which improves the major psychological growth indicators.(4)In the path that affects the psychological growth of teachers and postgraduates,female groups mainly focusing on natural sciences pay more attention to the tutor-student emotional experience,while male and lower-grade groups pay more attention to behavioral interaction;In the path that affects the interaction between teachers and postgraduates,the tutor does not value the difference in the quality of graduate students,lower-grade and natural science professional groups pay more attention to institutional environment.展开更多
Corporate social responsibility is the inevitable requirement for the survival and development of enterprises in modern society,as well as the basic guarantee for the sustainable development of economy and society.In ...Corporate social responsibility is the inevitable requirement for the survival and development of enterprises in modern society,as well as the basic guarantee for the sustainable development of economy and society.In order to analyze the driving factors of corporate social responsibility from both internal and external aspects,the dynamic model of corporate social responsibility was constructed,and the driving strategies of corporate social responsibility were also suggested.The driving factors of corporate social responsibility include not only the external constraints of policies,regulations and stakeholders,but also the internal requirements of the sustainable development of enterprises.Only when the external driving force is transformed into the spontaneous and conscious responsibility behavior of the enterprise,can the enterprise achieve its due effect.Moreover,in order to better fulfill the social responsibility,enterprise should build a management system of social responsibility,enhance the awareness of social responsibility,and promote the effective implementation of social responsibility projects.The relevant department should strengthen the all-round supervision of corporate social responsibility,and further improve the policies,laws and regulations related to social responsibility.Enterprises should strengthen communication with stakeholders,actively disclose social responsibility information,and constantly improve social responsibility behavior.By implementing social responsibility,enterprise can improve its business environment,enhance corporate brand image and core competitiveness,and promote the sustainable development of economy and society.展开更多
Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performa...Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performance and then adopts other mediation variables to explain the underlying mechanism.The empirical analyses are performed on a sample of 201 listed Chinese firms.The result shows that CSR has a weak negative impact on corporate perfbnnance while being positively influenced by corporate performance significantly.Further study finds the reason may be CSR requires financial support,but has little to do with increasing shareholder wealth.展开更多
The present paper discusses a design method for the head position in a Hard Disk Drive (HDD) control system. In the HDD control system, the sampling interval of the head position is constrained because of the hardwa...The present paper discusses a design method for the head position in a Hard Disk Drive (HDD) control system. In the HDD control system, the sampling interval of the head position is constrained because of the hardware specifications, but the hold interval of the control input is not constrained. In the present study, a multirate control system is designed, in which the sampling and the hold intervals are not equal. A multirate control law, which stabilizes a closed-loop system, is extended using newly introduced parameters such that the sample response of the plant output is maintained. Furthermore, intersample ripples in the steady state are eliminated using the new design parameters, which can be selected independently of the sample response. As a result, the intersample response can be improved independently of the sample response. The proposed method is applied to a benchmark problem of an HDD system, and its effectiveness is demonstrated.展开更多
Many earthquakes occurred during the period 1994 -1996 in Sichuan and Yunnan Provinces, Southwest China. Taking the process of the initial main phase recovery phase of the magnetic storm as the process of load-unload ...Many earthquakes occurred during the period 1994 -1996 in Sichuan and Yunnan Provinces, Southwest China. Taking the process of the initial main phase recovery phase of the magnetic storm as the process of load-unload response of the geomagnetic field to the solar wind, we have estimated and analyzed the distribution in time and space of the load-unload response ratio P(z) of the storm time disturbance daily variation of the vertical component Z of the geomagnetic field at ten stations in Southwest China. We found that the area with high ratio P(z) was just the area where moderately strong earthquakes would occur from 44 days to 15 months later. The relationship between the high ratio P(z) and weather disasters in both seismic and non-seismic areas is discussed briefly.展开更多
Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to e...Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more flexible.In this paper,a new method for designing the drive train parameters of cobot is proposed.Firstly,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design domain.Secondly,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design variables.Finally,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective optimization.Base on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial cobot.The result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a benchmark.The minimum resonance frequency of the joints is 42.70 Hz.展开更多
This paper presents a wavelet-based approach for estimating the response of the base-isolated structure under seismic ground motions. The seismic ground motion record is expressed as the multi-scale wavelet coefficien...This paper presents a wavelet-based approach for estimating the response of the base-isolated structure under seismic ground motions. The seismic ground motion record is expressed as the multi-scale wavelet coefficients which presents the time frequency characteristics of the seismic excitation. The wavelet domain governing differential equation between the wavelet coefficients of the excitation and response is derived. Numerical study on a one-storey base isolated structure is performed. The result shows that the wavelet based response computation method is of high precision.展开更多
文摘BACKGROUND This study examines the complex relationships among the neuroendocrine axis,gut microbiome,inflammatory responses,and gastrointestinal symptoms in patients with irritable bowel syndrome(IBS).The findings provide new insights into the pathophysiology of IBS and suggest potential therapeutic targets for improving patient outcomes.AIM To investigate the interactions between the neuroendocrine axis,gut microbiome,inflammation,and gastrointestinal symptoms in patients with IBS.METHODS Patients diagnosed with IBS between January 2022 and January 2023 were selected for the study.Healthy individuals undergoing routine check-ups during the same period served as the control group.Data were collected on neuroendocrine hormone levels,gut microbiome profiles,inflammatory biomarkers,and gastrointestinal symptomatology to analyze their interrelations and their potential roles in IBS pathogenesis.RESULTS IBS patients exhibited significant dysregulation of the neuroendocrine axis,with altered levels of cortisol,serotonin,and neuropeptides compared to healthy controls.The gut microbiome of IBS patients showed reduced diversity and specific alterations in bacterial genera,including Bifidobacterium,Lactobacillus,and Faecalibacterium,which were associated with neuroendocrine disturbances.Additionally,elevated levels of inflammatory markers,such as C-reactive protein,interleukin-6,and tumor necrosis factor-α,were observed and correlated with the severity of gastrointestinal symptoms like abdominal pain,bloating,and altered bowel habits.CONCLUSION The findings suggest that targeting the neuroendocrine axis,gut microbiome,and inflammatory pathways may offer novel therapeutic strategies to alleviate symptoms and improve the quality of life in IBS patients.
基金Project(50575228) supported by the National Natural Science Foundation of ChinaProject(07JJ3089) supported by the Hunan Provincial Natural Science Foundation of China
文摘As a new ionic polymer-metal composite(IPMC) for artificial muscle,the mechanical performance parameters and the relationship between the deformation and the electrical parameters of the IPMC were studied. With the digital speckle correlation method,the constitutive relationship of the IPMC was confirmed. With non-contact photography measurement,a cantilever setup was designed to confirm the relationship between the deformation of the IPMC film and the applied voltage. The relationship curve of tip displacement of the IPMC cantilever setup vs the voltage was achieved. The results indicate that the IPMC is isotropic,its elastic modulus is 232 MPa and Poisson ratio is 0.163. The curve achieved from the test of the tip displacement of the IPMC cantilever setup shows that the tip displacement reaches the maximum when the stimulated voltage is 5 V. And the tip displacement descends largely when the frequency of the applied voltage is between 30 mHz and 100 mHz.
基金supported by the National Natural Science Foundation of China(11002103 and 11032009)Shanghai Leading Academic Discipline(B302)
文摘Conditions for complete and lag synchronizations in drive-response systems are considered under the unified framework of generalized synchronization. The question is addressed that whether the synchronization conditions achieving complete synchronization is still valid for lag synchronization when the time delay of signal transmission between the drive and response systems increases from 0. Theoretical and numerical results show that whether the synchronization conditions is stable for the influence of the time delay of signal transmission depends on a particular form of equilibria of the drive and response systems. Furthermore, it seems that the less the number of the equilibria of the drive system, the more likely the synchronization conditions are stable for the time delay of signal trans- mission.
文摘Peninsular Malaysia is located and lies in a low seismic region. Although Malaysia is not located in the active fault seismic area, it is closed to the Sumatran active seismic zones. Tall building are fIequently felt the tremor generated fTom Sumatran subduction and fault zones especially in the west cost of Peninsular Malaysia such as Johor Bahru, Kuala Lumpur and Penang. Existing design response spectra was developed based on attenuation relationship for each subduction and fault zone. In this study, the design response spectra were developed based on various attenuation relationships for selected location in Kuala Lumpur area, namely, Mutiara Damansara, Bandar Petaling Jaya and Bandar Puteri Puchong. The development of design response spectra based on various attenuation relationships is more reliable in selecting the appropriate attenuation relationship for the study area. Seven attenuations have been chosen and results show that Megawati et al. are the most appropriate attenuation relation for fault zone, where the predicted PGA (peak ground acceleration) is 0.0187 g which is the proposed PGA value for this study area. This study also found that most of soil in the study area can be categorized into SD (stiff soil) according to site classification in the NEHRP 2000 Provision/UBC 97. Bandar petaling Jaya was found to be highest AF (amplification factor) of 3.74 for stiff soil and Mutiara Damansara with AF of 2.67 for very dense soil or soft rock. The proposed design response spectra for each location were developed based on UBC 1997 (Uniform Building Code 1997). The peak RSA (response spectrum acceleration) of 0.30 g for soil type SD for Bandar Petaling Jaya is the maximum level of acceleration on the soil surface with a period range of 0.10 to 0.52 seconds. All these values can be used for the seismic safety evaluation of existing structures and as a guideline in designing new structures to resist future earthquake, within the study area.
文摘This paper describes the experimental study on shock response of FDB (fluid dynamic bearing) spindle for HDDs (hard disk drives). The FDBs are widely used as rotating shaft support elements for HDD spindle motors. Recently, the opportunity for the HDD spindle motors exposed to external vibration has been increasing because the HDDs are used for various information related equipment such as mobile PCs (personal computers), video cameras, car navigation systems and so on. Hence, the rotating shaft has a possibility to come in contact with the bearing by external shocks and it causes wear or seizure to the bearing surface. To avoid the problem, it is extremely important to know how the spindle moves against the large shock on HDDs experimentally. However, as far as the authors know, there are few experimental studies treating the shock response of HDD spindles. In this paper, firstly, we propose a new test rig and experimental method for shock response of FDB spindles. Then the shock tests against the radial and axial disturbance on FDB spindle for 2.5" HDD are conducted. Finally, the experimental results of shock response waveforms and maximum displacement of disk are shown.
文摘This paper studies the generalized synchronization of a class of drive-response neural networks with time-varying delay. When the topological structures of the drive-response neural networks are known, by designing an appropriate nonlinear adaptive controller, the generalized synchronization of these two networks is obtained based on Lyapunov stability theory and LaSalle’s invariance principle.
基金support from the National Natural Science Foundation of China (Grant No.40872077)National Major Science and Technology Project of China (Grant No. 2011ZX05009-002)Open Project Foundation of Ministry of Education Key Laboratory of Tectonics and Petroleum Resources (Grant No. TPR-2011-09)
文摘The sequence stratigraphy framework of Paleogene of Qikou Sag has been built in this paper. The evolution law of episodic subsidence in Qikou Sag has been expounded, with the analysis of the characteristic of sequence thickness, as well as the study of consedimental tectonic activity, subsidence history, paleogeomorphology and the coupling relationship among them. The faults controlling action was the dominant mechanism during rifting stage I , as the depression was the dominant mechanism during rifting stage III, which embodies a process from intense disparity fault depression to integral subsidence. Meanwhile, under the control of regional faulting and later stage depression, subsidence rate centers and paleogeomorphic concave centers are always corresponding to the sequence thickness centers, and the changes of subsidence centers and paleogeomorphology concave centers are consistent with the migration of thickness centers, which presents the restriction, coupling and response among them and clarifies the law that tectonic activity controls the basin fill by means of controlling the subsidence rate and paleogeomorphology from contributing factor angle. On this basis, the dynamic evolution of the composite pattern of structure-subsidence-deposition in the fault controlling actic region during the three rifting stages and their petroleum geological significance has been discussed.
基金supported by the National Natural Science Foundation of China (11172233, 10932009 and 10972181)Program for New Century Excellent Talents in University+1 种基金the Shaanxi Project for Young New Star in Science & TechnologyNPU Foundation for Fundamental Research and New Faculties and Research Area Project
文摘A convenient and universal residue calculus method is proposed to study the stochastic response behaviors of an axially moving viscoelastic beam with random noise excitations and fractional order constitutive relationship, where the random excitation can be decomposed as a nonstationary stochastic process, Mittag-Leffler internal noise, and external stationary noise excitation. Then, based on the Laplace transform approach, we derived the mean value function, variance function and covariance function through the Green's function technique and the residue calculus method, and obtained theoretical results. In some special case of fractional order derivative α , the Monte Carlo approach and error function results were applied to check the effectiveness of the analytical results, and good agreement was found. Finally in a general-purpose case, we also confirmed the analytical conclusion via the direct Monte Carlo simulation.
文摘Tonle Sap Lake is the largest river-connected lake, buffer area and ecological zone of Mekong River, which plays a huge role in dispelling flood peak and compensating water, and the conservation of biological diversity. The river-lake relationship between Mekong River and Tonle Sap Lake is unique and has always been a major focus in the international community. The land terrain and under-water topography were used to analyze the morphological characteristics of Cambodia Mekong Delta and Tonle Sap Lake. Long series of hydrological data of river-lake controlling stations were used to analyze the water level variation characteristics and water volume exchange pattern between Mekong River and Tonle Sap Lake, and the response relationship to river-lake morphological characteristics were also researched. The results show that: Cambodia Mekong Delta and Tonle Sap Lake Area is low-lying and flat with gentle channel gradient and water surface gradient, making the relationship between water level and area (or volume) smooth. The channel storage capacity of Mekong River and Tonle Sap River is not enough compared to the inflow, so vast flooding plain is extremely prone to be inundated, making the flood relationships between the left and right banks become very complicated. Tonle Sap Lake is a seasonal freshwater lake with water flowing in and flowing out, and the timing and intensity of water exchange with Mekong River are closely related to the water flow resistance at the exit section of Tonle Sap Lake and the cross-sectional area of Tonle Sap River, which can be reflected by the river-lake water level difference and the water level of Tonle Sap River. Affected by the river-lake morphological characteristics, the water exchange intensity between Mekong River and Tonle Sap Lake is great. Tonle Sap Lake not only stores 14.4% of flood volume (39.7 billion m3) from the Mekong River every year, but also supplies 29.7% of dry water (69.4 billion m3) to the Mekong River. Influenced by the adjustment of the floodplain, the water level fluctuation of Mekong River and Tonle Sap Lake is slow, and the rising and droop rates of water level are positively correlated with the floodplain storage area. The research results will help to understand the relationship mechanism between Mekong River and Tonle Sap Lake and provide a scientific basis for the comprehensive governance of Cambodia Mekong Delta and Tonle Sap Lake Area.
基金supported by the 2016 graduate research project of Guizhou University of Finance and Economics: "Enterprise Innovation, Social Responsibility: Interaction Mechanism and Empirical Test"
文摘Under the new normal economic growth, lack of motivation, structural imbalances in the economy, the shortage of resources, resource utilization inefficiency, environmental damage and other issues have become increasingly prominent, enterprises as the carrier of economy is one of the root of the problem. Research on enterprise innovation and corporate social responsibility issues, it is conducive to the development of enterprise itself and the transformation of Chinese economy. This paper reviewed the research status of relationships between innovation and corporate social responsibility, through comb the aspects of the definitions and evolution of enterprise innovation and social responsibility, also include both the relationship and the new way(responsible innovation) of combination of them, we found the presence of index system is not perfect, and lack of in-depth comprehensive study and opportunities for future research is prospected.
文摘The increasing use of diesel-powered equipment in confined spaces(underground mines) has the potential to over expose underground miners under the threat of diesel particulate matter(DPM). Miners in underground mines can be exposed to DPM concentrations far more than works in other industries. A great number of animal and epidemiological studies have shown that both short-term and long-term DPM exposure have adverse health effect. Based on reviews of related studies, especially some recent evidence, this paper investigated the long and short-term health effects based on animal studies and epidemiological studies. The exposure-response relationship studies were also explored and compared to the current DPM regulation or standards in some countries. This paper found that the DPM health effect studies specifically for miners are not sufficient to draw solid conclusions, and a recommendation limit of DPM concentration can be put in place for better protection of miners from DPM health risk. Current animal studies lack the use of species that have similar lung functions as human for understanding the cancer mode of action in human. And finally, the DPM health hazard will continue to be a challenging topic before the mode of action and reliable exposure-response relationship are established.
文摘The dose-response curves obtained by premature condensed chromosome (PCC)and conventional cellular genetic methods can be represented by two linear equations. The ratiO of the slopes, Kpcc/KM,, is about 28. In comparison to the conventional method, the PCC method has many advantages; e,g. it is faster, simpler, more sensitive and accurate. Its significance in the study of radiation damage is also discussed.
文摘A harmonious relationship between teachers and postgraduates presents the comprehensive value of psychological education,which guarantees training quality and acts as an effective carrier of mental health education of the postgraduates.Based on Bandura’s theory of reciprocal determinism and Austin’s input-output theory,this paper constructs a model concerning the value of psychological education in the tutor-student relationship.The path of realization is also explored in a structural equation model through a questionnaire survey of 1112 graduate supervisors and administrators in medical colleges.The experimental result indicates that(1)The interaction between teachers and postgraduates promotes the value of psychological education in the highest measure,among which the quality and frequency of tutor-student communication,mutual trust,and respect act as the key influencing indicators.(2)Tutor’s professional quality is considered as the fundamental driving force in the realization of psychological education value in the tutor-student relationship,the maximum mediating effect is observed in the developing path of tutor’s professional quality-interaction behavior between teachers and postgraduates-psychological growth of teachers and postgraduates.(3)The objective results obtained by teachers and postgraduates,such as the improvement of quality and quantity,positively promote the overall quality of life satisfaction of both sides,which improves the major psychological growth indicators.(4)In the path that affects the psychological growth of teachers and postgraduates,female groups mainly focusing on natural sciences pay more attention to the tutor-student emotional experience,while male and lower-grade groups pay more attention to behavioral interaction;In the path that affects the interaction between teachers and postgraduates,the tutor does not value the difference in the quality of graduate students,lower-grade and natural science professional groups pay more attention to institutional environment.
文摘Corporate social responsibility is the inevitable requirement for the survival and development of enterprises in modern society,as well as the basic guarantee for the sustainable development of economy and society.In order to analyze the driving factors of corporate social responsibility from both internal and external aspects,the dynamic model of corporate social responsibility was constructed,and the driving strategies of corporate social responsibility were also suggested.The driving factors of corporate social responsibility include not only the external constraints of policies,regulations and stakeholders,but also the internal requirements of the sustainable development of enterprises.Only when the external driving force is transformed into the spontaneous and conscious responsibility behavior of the enterprise,can the enterprise achieve its due effect.Moreover,in order to better fulfill the social responsibility,enterprise should build a management system of social responsibility,enhance the awareness of social responsibility,and promote the effective implementation of social responsibility projects.The relevant department should strengthen the all-round supervision of corporate social responsibility,and further improve the policies,laws and regulations related to social responsibility.Enterprises should strengthen communication with stakeholders,actively disclose social responsibility information,and constantly improve social responsibility behavior.By implementing social responsibility,enterprise can improve its business environment,enhance corporate brand image and core competitiveness,and promote the sustainable development of economy and society.
文摘Corporations actively fulfilling corporate social responsibility(CSR)is of more significance to society's sustainable development nowadays.This research discusses the interaction between CSR and corporate performance and then adopts other mediation variables to explain the underlying mechanism.The empirical analyses are performed on a sample of 201 listed Chinese firms.The result shows that CSR has a weak negative impact on corporate perfbnnance while being positively influenced by corporate performance significantly.Further study finds the reason may be CSR requires financial support,but has little to do with increasing shareholder wealth.
文摘The present paper discusses a design method for the head position in a Hard Disk Drive (HDD) control system. In the HDD control system, the sampling interval of the head position is constrained because of the hardware specifications, but the hold interval of the control input is not constrained. In the present study, a multirate control system is designed, in which the sampling and the hold intervals are not equal. A multirate control law, which stabilizes a closed-loop system, is extended using newly introduced parameters such that the sample response of the plant output is maintained. Furthermore, intersample ripples in the steady state are eliminated using the new design parameters, which can be selected independently of the sample response. As a result, the intersample response can be improved independently of the sample response. The proposed method is applied to a benchmark problem of an HDD system, and its effectiveness is demonstrated.
基金This project was sponsored by the China Seismlogical Bureau (No. 95-04-01, China.
文摘Many earthquakes occurred during the period 1994 -1996 in Sichuan and Yunnan Provinces, Southwest China. Taking the process of the initial main phase recovery phase of the magnetic storm as the process of load-unload response of the geomagnetic field to the solar wind, we have estimated and analyzed the distribution in time and space of the load-unload response ratio P(z) of the storm time disturbance daily variation of the vertical component Z of the geomagnetic field at ten stations in Southwest China. We found that the area with high ratio P(z) was just the area where moderately strong earthquakes would occur from 44 days to 15 months later. The relationship between the high ratio P(z) and weather disasters in both seismic and non-seismic areas is discussed briefly.
基金Supported by National Key Research and Development Program of China (Grant Nos.2022YFB4703000,2019YFB1309900)。
文摘Automation advancements prompts the extensive integration of collaborative robot(cobot)across a range of industries.Compared to the commonly used design approach of increasing the payload-to-weight ratio of cobot to enhance load capacity,equal attention should be paid to the dynamic response characteristics of cobot during the design process to make the cobot more flexible.In this paper,a new method for designing the drive train parameters of cobot is proposed.Firstly,based on the analysis of factors influencing the load capacity and dynamic response characteristics,design criteria for both aspects are established for cobot with all optimization design criteria normalized within the design domain.Secondly,with the cobot in the horizontal pose,the motor design scheme is discretized and it takes the joint motor diameter and gearbox speed ratio as optimization design variables.Finally,all the discrete values of the optimization objectives are obtained through the enumeration method and the Pareto front is used to select the optimal solution through multi-objective optimization.Base on the cobot design method proposed in this paper,a six-axis cobot is designed and compared with the commercial cobot.The result shows that the load capacity of the designed cobot in this paper reaches 8.4 kg,surpassing the 5 kg load capacity commercial cobot which is used as a benchmark.The minimum resonance frequency of the joints is 42.70 Hz.
文摘This paper presents a wavelet-based approach for estimating the response of the base-isolated structure under seismic ground motions. The seismic ground motion record is expressed as the multi-scale wavelet coefficients which presents the time frequency characteristics of the seismic excitation. The wavelet domain governing differential equation between the wavelet coefficients of the excitation and response is derived. Numerical study on a one-storey base isolated structure is performed. The result shows that the wavelet based response computation method is of high precision.