Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varietie...Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.展开更多
A generic pulse width modulation(PWM) strategy is proposed for the multi-leg voltage source inverter(VSI).First, the multi-leg VSI is modeled, which is independent from the load structure. Secondly, the proposed P...A generic pulse width modulation(PWM) strategy is proposed for the multi-leg voltage source inverter(VSI).First, the multi-leg VSI is modeled, which is independent from the load structure. Secondly, the proposed PWM strategy is deduced by inverting the mathematical model of the multileg VSI. According to the relationship between the leg number of VSIs and the phase number of electrical machines, the multi-leg VSI-fed machine drives are classified into two types:matched and unmatched applications. The leg numbers of VSIs and the phase number of electrical machines are equal in matched applications while they are different in unmatched applications. The existing PWM strategies cannot be directly used for both matched and unmatched applications. However,the proposed PWM strategy can be general for both matched and unmatched applications, and no modifications are required. The effectiveness of the proposed PWM strategy is verified by experimental results.展开更多
AIM: To study the effect of sulindac on colon cancer induction in mice. METHODS: The chemo-preventive action of 80 ppm sulindac fed during initiation and post-initiation and 100 ppm sulindac fed during progressive sta...AIM: To study the effect of sulindac on colon cancer induction in mice. METHODS: The chemo-preventive action of 80 ppm sulindac fed during initiation and post-initiation and 100 ppm sulindac fed during progressive stages of induction of colon carcinogenesis in mice was investigated using 1,2-dimethylhydrazine (DMH). Using the terminal deoxynudeobdyl transferase-mediated dUTP nick-end labeling (TUNEL) technique and PCNA immunohistochemical staining, we observed the apoptotic and proliferative cell density changes at different carcinogenic stages and the effect of sulindac on these two phenomena. RESULTS: Dietary sulindac significantly inhibited the incidence of colonic neoplasmas in mice. Compared with the control group, feeding sulindac during initiation and post-initiation stages inhibited the incidence by 46.7-50.4%, and feeding sulindac during progressive stages inhibited the incidence by 41.1%. Animals that were fed sulindac showed less serious pathological changes than those that were fed the control diet (P<0.01, H=33.35). There was no difference in the density of proliferating cells among those groups which were or were not fed sulindac. In the same period, feeding sulindac resulted in a higher density of apoptotic cells than feeding control diet. CONCLUSION: Sulindac has an anti-carcinogenic function in mice. Its effect on preventing colon carcinogenesis is better than its effect on treating established tumors. By inducing apoptosis, sulindac inhibited the development of colon cancer and delayed canceration. Sulindac has no effect on proliferation. The anti-carcinogenic properties of sulindac are most effective in the moderate and severe stages of dysplasia and canceration.展开更多
The operation of a motor drive for high-power, high-speed applications, especially for the permanent-magnet synchronous AC motors with regeneration capability is presented. Power system utilizes a SVHPWM (space-vecto...The operation of a motor drive for high-power, high-speed applications, especially for the permanent-magnet synchronous AC motors with regeneration capability is presented. Power system utilizes a SVHPWM (space-vector-based hybrid pulse width modulation) for a reduced harmonic distortion and switching loss. Associated electromagnetic interference mitigation and cooling requirements are significantly reduced. Voltage source inverter drives a three-phase MLC200 flywheel. The modularity of the proposed topology also simplifies overall system design and manufacturability. The system topology and control strategy are discussed. Simulation results are presented to illustrate the harmonic distortion and switching loss reduction and reduced line current ripple.展开更多
Bacterial quorum sensing (QS) has attracted much interests and it is an important process of cell communication. Recently, Bassler et al. studied the phenomena of QS regulated by small RNAs and the experimental data...Bacterial quorum sensing (QS) has attracted much interests and it is an important process of cell communication. Recently, Bassler et al. studied the phenomena of QS regulated by small RNAs and the experimental data showed that smafl RNAs played important role in the QS of Vibrio harveyi and it can permit the fine-tuning of gene regulation and mmntenance of homeostasis. According to Michaelis-Menten kinetics and mass action law in this paper, we construct a mathematical model to investigate the mechanism induced QS by coexist of small RNA and signal molecular (AI) and show that there are periodic oscillation when the time delay and Hill coefficient exceed a critical value and the periodic oscillation produces the change of concentration and induces QS. These results are fit to the experimental results. In the meanwhile, we also get some theoretical value of Hopf Bifurcation on time deday. In addition, we also find this network is robust against noise.展开更多
An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting ...An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting mechanism is proposed. It considers the non-linearity and time variations in the control process and uses Dynamic Fuzzy Neural Networks (D-FNN). The inverse characteristics of the system are studied. An adaptive on-line learning and error compensation mechanism guarantees sys- tem real-time performance and reliability. Parameters from a German Eickhoff SL500 shearer were used with Maflab/Simulink to simulate a height adjusting control system. Simulation shows that the trace error of a D-FNN controller is smaller than that of a PID controller. Also, the D-FNN control scheme has good generalization and tracking performance, which allow it to satisfy the needs of a shearer height adjusting system.展开更多
Through the analysis on the current situation of the souvenirs in Jiangxi red revolutionary museums, the new design positioning of the souvenirs is discussed, and also the development direction of the souvenirs is stu...Through the analysis on the current situation of the souvenirs in Jiangxi red revolutionary museums, the new design positioning of the souvenirs is discussed, and also the development direction of the souvenirs is studied from culture connotation excavation, buying motivation, buying groups, the combination of design with technology, and pre-sale, in-sale, and after-sale services. On the basis of preserving the traditional revolutionary culture, the revolutionary stories are reshaped using modem design language and science and technology, so that new living space and development direction are given to the souvenirs of red revolution, the sales of the souvenirs are promoted, the economic benefits of the red revolutionary museums are improved, the red tourism is more effectively promoted, and Jiangxi red revolutionary culture is developed and expanded.展开更多
Adequate energy storage is essential for sustaining healthy life. Lipid droplet (LD) is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient cond...Adequate energy storage is essential for sustaining healthy life. Lipid droplet (LD) is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient conditions. Energy storage capacity of LDs is primarily dependent on the sizes of LDs. Enlargement and growth of LDs is controlled by two molecular pathways: neutral lipid synthesis and atypical LD fusion. Shrinkage of LDs is mediated by the degradation of neutral lipids under energy demanding conditions and is controlled by neutral cytosolic lipases and lysosomal acidic lipases. In this review, we summarize recent progress regarding the regulatory pathways and molecular mechanisms that control the sizes and the energy storage capacity of LDs.展开更多
The fundamental unit of rapid, physiological color change in vertebrates is the dermal chromato- phore unit. This unit, comprised of cellular associations between different chromatophore types, is relatively conserved...The fundamental unit of rapid, physiological color change in vertebrates is the dermal chromato- phore unit. This unit, comprised of cellular associations between different chromatophore types, is relatively conserved across the fish, amphibian, and reptilian species capable of physiological color change and numerous attempts have been made to understand the nature of the four major chro- matophore types (melanophores, erythrophores, xanthophores, and iridophores) and their bio- chemical regulation. In this review, we attempt to describe the current state of knowledge regard- ing what classifies a pigment cell as a dynamic chromatophore, the unique characteristics of each chromatophore type, and how different hormones, neurotransmitters, or other signals direct pig- ment reorganization in a variety of vertebrate taxa.展开更多
文摘Vibrations or dither's are features of the PWM servo control system in their steady outputs. On the grounds of analyses and experiments of a PWM pneumatic servo control system, the paper puts forward four varieties of PWM modulation methods, and concludes on the relationship between dithers and the different methods, and then discusses the influence of friction to the dithers. Results from experiments regarding the dynamic and static responses on the given system support the theories presented.
基金The National Natural Science Foundation of China(No.51607038)the Natural Science Foundation of Jiangsu Province(No.BK20160673)+1 种基金the National Basic Research Program of China(973 Program)(No.2013CB035603)China Postdoctoral Science Foundation(No.2015M581697,2016T90401)
文摘A generic pulse width modulation(PWM) strategy is proposed for the multi-leg voltage source inverter(VSI).First, the multi-leg VSI is modeled, which is independent from the load structure. Secondly, the proposed PWM strategy is deduced by inverting the mathematical model of the multileg VSI. According to the relationship between the leg number of VSIs and the phase number of electrical machines, the multi-leg VSI-fed machine drives are classified into two types:matched and unmatched applications. The leg numbers of VSIs and the phase number of electrical machines are equal in matched applications while they are different in unmatched applications. The existing PWM strategies cannot be directly used for both matched and unmatched applications. However,the proposed PWM strategy can be general for both matched and unmatched applications, and no modifications are required. The effectiveness of the proposed PWM strategy is verified by experimental results.
基金Supported by the Natural Science Foundation of Tianjin, No. 973611311
文摘AIM: To study the effect of sulindac on colon cancer induction in mice. METHODS: The chemo-preventive action of 80 ppm sulindac fed during initiation and post-initiation and 100 ppm sulindac fed during progressive stages of induction of colon carcinogenesis in mice was investigated using 1,2-dimethylhydrazine (DMH). Using the terminal deoxynudeobdyl transferase-mediated dUTP nick-end labeling (TUNEL) technique and PCNA immunohistochemical staining, we observed the apoptotic and proliferative cell density changes at different carcinogenic stages and the effect of sulindac on these two phenomena. RESULTS: Dietary sulindac significantly inhibited the incidence of colonic neoplasmas in mice. Compared with the control group, feeding sulindac during initiation and post-initiation stages inhibited the incidence by 46.7-50.4%, and feeding sulindac during progressive stages inhibited the incidence by 41.1%. Animals that were fed sulindac showed less serious pathological changes than those that were fed the control diet (P<0.01, H=33.35). There was no difference in the density of proliferating cells among those groups which were or were not fed sulindac. In the same period, feeding sulindac resulted in a higher density of apoptotic cells than feeding control diet. CONCLUSION: Sulindac has an anti-carcinogenic function in mice. Its effect on preventing colon carcinogenesis is better than its effect on treating established tumors. By inducing apoptosis, sulindac inhibited the development of colon cancer and delayed canceration. Sulindac has no effect on proliferation. The anti-carcinogenic properties of sulindac are most effective in the moderate and severe stages of dysplasia and canceration.
文摘The operation of a motor drive for high-power, high-speed applications, especially for the permanent-magnet synchronous AC motors with regeneration capability is presented. Power system utilizes a SVHPWM (space-vector-based hybrid pulse width modulation) for a reduced harmonic distortion and switching loss. Associated electromagnetic interference mitigation and cooling requirements are significantly reduced. Voltage source inverter drives a three-phase MLC200 flywheel. The modularity of the proposed topology also simplifies overall system design and manufacturability. The system topology and control strategy are discussed. Simulation results are presented to illustrate the harmonic distortion and switching loss reduction and reduced line current ripple.
基金Supported by National Natural Science Foundation of China under Grant Nos. 10802043 and 10832006, Program for Science & Technology Innovation Talents in Universities of Henan under Grant No. 2009HASTIT033 and Key Disciplines of Shanghai municipality ($30104)
文摘Bacterial quorum sensing (QS) has attracted much interests and it is an important process of cell communication. Recently, Bassler et al. studied the phenomena of QS regulated by small RNAs and the experimental data showed that smafl RNAs played important role in the QS of Vibrio harveyi and it can permit the fine-tuning of gene regulation and mmntenance of homeostasis. According to Michaelis-Menten kinetics and mass action law in this paper, we construct a mathematical model to investigate the mechanism induced QS by coexist of small RNA and signal molecular (AI) and show that there are periodic oscillation when the time delay and Hill coefficient exceed a critical value and the periodic oscillation produces the change of concentration and induces QS. These results are fit to the experimental results. In the meanwhile, we also get some theoretical value of Hopf Bifurcation on time deday. In addition, we also find this network is robust against noise.
基金support for this work, provided by the National High Technology Research and Development Program of China (No2008AA062202)China University of Mining & Technology Scaling Program
文摘An intelligent shearer height adjusting system is a key technology for mining at a man-less working face. A control strategy for a shearer height adjusting system based on a mathematical model of the height adjusting mechanism is proposed. It considers the non-linearity and time variations in the control process and uses Dynamic Fuzzy Neural Networks (D-FNN). The inverse characteristics of the system are studied. An adaptive on-line learning and error compensation mechanism guarantees sys- tem real-time performance and reliability. Parameters from a German Eickhoff SL500 shearer were used with Maflab/Simulink to simulate a height adjusting control system. Simulation shows that the trace error of a D-FNN controller is smaller than that of a PID controller. Also, the D-FNN control scheme has good generalization and tracking performance, which allow it to satisfy the needs of a shearer height adjusting system.
文摘Through the analysis on the current situation of the souvenirs in Jiangxi red revolutionary museums, the new design positioning of the souvenirs is discussed, and also the development direction of the souvenirs is studied from culture connotation excavation, buying motivation, buying groups, the combination of design with technology, and pre-sale, in-sale, and after-sale services. On the basis of preserving the traditional revolutionary culture, the revolutionary stories are reshaped using modem design language and science and technology, so that new living space and development direction are given to the souvenirs of red revolution, the sales of the souvenirs are promoted, the economic benefits of the red revolutionary museums are improved, the red tourism is more effectively promoted, and Jiangxi red revolutionary culture is developed and expanded.
基金supported by the National Natural Science Foundation of China(31420040,31321003 to Peng Li,31501089 to Jinhai Yu)the National Basic Research Program(2013CB530602 to Peng Li)the China Postdoctoral Science Foundation(2015M581079 to Jinhai Yu)
文摘Adequate energy storage is essential for sustaining healthy life. Lipid droplet (LD) is the subcellular organelle that stores energy in the form of neutral lipids and releases fatty acids under energy deficient conditions. Energy storage capacity of LDs is primarily dependent on the sizes of LDs. Enlargement and growth of LDs is controlled by two molecular pathways: neutral lipid synthesis and atypical LD fusion. Shrinkage of LDs is mediated by the degradation of neutral lipids under energy demanding conditions and is controlled by neutral cytosolic lipases and lysosomal acidic lipases. In this review, we summarize recent progress regarding the regulatory pathways and molecular mechanisms that control the sizes and the energy storage capacity of LDs.
文摘The fundamental unit of rapid, physiological color change in vertebrates is the dermal chromato- phore unit. This unit, comprised of cellular associations between different chromatophore types, is relatively conserved across the fish, amphibian, and reptilian species capable of physiological color change and numerous attempts have been made to understand the nature of the four major chro- matophore types (melanophores, erythrophores, xanthophores, and iridophores) and their bio- chemical regulation. In this review, we attempt to describe the current state of knowledge regard- ing what classifies a pigment cell as a dynamic chromatophore, the unique characteristics of each chromatophore type, and how different hormones, neurotransmitters, or other signals direct pig- ment reorganization in a variety of vertebrate taxa.