OALib Journal期刊

ISSN: 2333-9721




2018 ( 4 )

2017 ( 121 )

2016 ( 150 )

2015 ( 1838 )


匹配条件: “ Shuhan Yu” ,找到相关结果约58392条。
A New Strategy for BLDC Sensorless Control System and Its Application in Horizontal Well Tractor  [PDF]
Shuhan Yu, Yongjun Chen
Open Access Library Journal (OALib Journal) , 2017, DOI: 10.4236/oalib.1103844
The positionless brushless DC motor has the advantages of simple structure, good speed performance and high efficiency. It has become the best choice for horizontal well tractor. This paper introduces a set of brushless DC motor control system, gives the hardware structure of the system and brushless DC motor without Hall sensor control flow chart and the host computer communication interface protocol which solves the problem of phase lag in the case of high speed motor. Aiming at the problem that the parameters of the motor can not be monitored, the host computer monitoring program based on c# can be designed to monitor the parameters of the motor in real time. The experimental results show that the control system can make the motor run smoothly at different speeds, and can monitor the parameters of the motor in real time, suitable for the horizontal well logging and so on the motor control system requires relatively high industrial environment.
Dynamic Parallel and Distributed Graph Cuts
Miao Yu,Shuhan Shen,Zhanyi Hu
Computer Science , 2015,
Abstract: Graph-cuts are widely used in computer vision. In order to speed up the optimization process and improve the scalability for large graphs, Strandmark and Kahl introduced a splitting method to split a graph into multiple subgraphs for parallel computation in both shared and distributed memory models. However, this parallel algorithm (parallel BK-algorithm) does not have a polynomial bound on the number of iterations and is found non-convergent in some cases due to the possible multiple optimal solutions of its sub-problems. To remedy this non-convergence problem, in this work we first introduce a merging method capable of merging any number of those adjacent sub-graphs which could hardly reach an agreement on their overlapped region in the parallel BKalgorithm. Based on the pseudo-boolean representations of graphcuts,our merging method is shown able to effectively reuse all the computed flows in these sub-graphs. Through both the splitting and merging, we further propose a dynamic parallel and distributed graph-cuts algorithm with guaranteed convergence to the globally optimal solutions within a predefined number of iterations. In essence, this work provides a general framework to allow more sophisticated splitting and merging strategies to be employed to further boost performance. Our dynamic parallel algorithm is validated with extensive experimental results.
Design of Drive System for Sensorless Brushless DC Motor Based on Model Reference Adaptive Control and Its Application in Horizontal Well Tractor  [PDF]
Zhou He, Yongjun Chen, Bo Ruan, Shuhan Yu, Junwen Zhou
Open Access Library Journal (OALib Journal) , 2018, DOI: 10.4236/oalib.1104267
The actual working environment temperature of the horizontal well tractor is too high, which leads to position sensor of general brushless DC motor (BLDCM) cannot work normally. Therefore, the position sensorless drive system is designed to overcome the problems caused by the position sensor in the actual working conditions. The principle of sensorless BLDCM work is introduced in detail, And drive system of Sensorless BLDCM was established by using simulation software. The use of three stage start make motor smoothly start, the motor speed detection based on model reference adaptive control (MRAC), ensures accurate commutation. Finally, the hardware and software design of the BLDCM system based on digital signal controller (DSC) is introduced and tested. The experimental results show that the drive system can start the BLDCM smoothly in the high temperature environment, and can quickly track the given speed, which meet the actual work demand of the horizontal well tractor.
Research on Permanent Magnet Synchronous Motor Driver System of Horizontal Well Tractor  [PDF]
Zhou He, Yongjun Chen, Shuhan Yu, Junwen Zhou, Yang Shen, Kuan Shi
Open Access Library Journal (OALib Journal) , 2017, DOI: 10.4236/oalib.1104237
Nowadays, horizontal well technology is being applied to the development of oilfield production capacity more and more. The horizontal well tractor can effectively solve the problem that the instrument can not get to the target layer by gravity. However, in actual conditions, Brushless DC motor (BLDCM) there is a large torque ripple problem, resulting in motor running is not smooth, vibration and noise is too large, can not meet the demand. Therefore, propose horizontal well tractor PMSM sine wave drive technology. The paper discusses the mathematical model of permanent magnet synchronous motor, analyzes the working principle of space vector pulse width modulation (SVPWM) technology, and establishes a speed and current double closed-loop space vector control system of the permanent magnet synchronous motor by using PSIM simulation software. Simulation results verify the robustness of the control system, and the torque ripple of the motor is small, in line with the working conditions of horizontal well tractor.
MI + MI + CI: Could MI Theory, Multidisciplinary Instruction, and A Community of inquiry, Sum Up to Math Engagement?
Janice-Lynn Shuhan
Analytic Teaching and Philosophical Praxis , 2006,
Abstract: This theoretical piece entertains the notion of increasing math class engagement through a combination of nontraditional frameworks. Research shows low student motivation and achievement in mathematics and the inability to transfer math concepts into real-life situations. Research also shows that that these deficits result from using traditional teaching methods. In this paper I propose a pedagogical blend of three existing and progressively popular frameworks: The process of teaching to Howard Gardner’s multiple intelligences, as a means of maximizing student learning in mathematics, is a way for students to make meaningful connections and relationships. The process of relating and linking two or more disciplines to mathematics is a way to help students make meaningful connections to real-life situations. Thirdly, the process of enabling a cooperative learning environment, whereby group discourse is supported in a community of inquiry setting, is a way to help students build sociocultural and interpersonal relationships, as well as increase their engagement in the learning process. The letter in the word team stands fortogether everyone achieves more—John LounsburyThe purpose of this thought piece is to offer a theoretical argument that supports the relevance ofincorporating an interdisciplinary approach to teaching. By virtue of its integrated and comparativeformat, interdisciplinarity presents the potential foundation for developing our eight intelligences, andthe MI Theory provides an effective instructional framework for structuring interdisciplinary lessons.Another type of contemporary methodology that supports this marriage of the intelligences andinterdisciplinary education in its effort to develop critical thought is cooperative learning.The variable expression in the title of this paper represents a blend of these conceptual frameworksand their potential for facilitating math engagement in adolescents. My discussion focuses on the followingconceptual frameworks: Gardner’s Multiple Intelligences Theory (1983, 1991, 1993b, 1993c, 1997) as itrelates to the multidisciplinary model of teaching, and the Community of Inquiry model (Splitter & Sharp, 1995) as it relates to cooperative learning and Vygotsky’s Zone of Proximal Development(ZPD) in small group settings (1988). As a seasoned secondary mathematics teacher in an urban high school, I have become increasingly interested in teaching to the individual intelligences (or individual strengths) of my math students via interdisciplinary lesson formats and special student-designed projects. From my pe
The influence of Annexin32, a new Ca2+-dependent phospholipid-binding protein, on coagulation time and thrombosis
Yi Zhang,Ruiwen Chen,Shuhan Sun
Science China Life Sciences , 2002, DOI: 10.1360/02yc9021
Abstract: The pharmacodynamics of Annexin32, a new Ca2+-dependent phospholipid-binding protein, was studied by measuring coagulation time in rabbits and venous thrombosis in rabbits and rats. Rabbits and rats were given Annexin32 by intravenous administration. Then Kaolin partial thromboplastin time (KPTT), thrombosis in vitro and in vivo were assayed. The results showed that KPTT of rabbits was prolonged (p < 0.01), and the length and weight of thrombus in vitro were reduced (p < 0.01) after administration of Annexin32 at 1 mg/kg. It also inhibited thrombosis in vivo and reduced the weight of venous thrombus significantly in rats (p < 0.01). All these results suggested that Annexin32 possesses the characteristic of antithrombotic effect and fewer side effects on coagulation time.
Homology modeling threedimensional structure of AnxB1 and reducing its immunogenicity by sequence-deleted mutagenesis
Yan Hongli,Song Yunlong,Liu Fan,He Yan,Sun Shuhan
Science China Life Sciences , 2004, DOI: 10.1360/03yc0085
Abstract: AnxB1, a novel annexin previously isolated from Cysticercus cellulose, shows high thrombi affinity and anticoagulant activity in vivo. In order to investigate the relationship between structure and biological function, a predicted three-dimensional (3D) model of AnxB1 was generated by homology modeling. This model contains four homologous internal-domains and the C/ga trace of domain I, II and IV shows high similarity. Based on the structure characterization, four sequence-deleted mutants were constructed and expressed as GST fusion proteins in E. coli. Two of the mutants, GST-M3 and GST-M4 reserved high anticoagulant activity (p<0.01 vs. GST). Furthermore, compared with the wild type GST-AnxB1, the immunogenicity of GST-M3 and GST-M4 was reduced significantly (p<0.01) and the molecular weight was lowered to 27 kD and 34 kD, respectively. These observations laid a solid foundation for further study on developing new thrombolytic agents with higher efficiency and lower side effect.
An Ecological Balanced Fertilization Model Based on Chemical and Microbial Compound Fertilization
Rongbiao Zhang,Ning Yang,Yuqi Zhao,Shuhan Li
Advance Journal of Food Science and Technology , 2012,
Abstract: This study proposed an Ecological Balanced Fertilization Models (EBFM) based on microbial compound fertilizer. We selected nine evaluating factors as Minimum Data Set (MDS). This MDS includes nutrition and microorganisms. According to the composition of chemistry nutrients to soil, microbial fertilizer and the level of effective fertilizer nutrient supply, we use the EBFM of the specific crops to develop the ratio of various elements. Finally, the Weighted Fuzzy Clustering Algorithm (WFCA) is used to evaluate the soil nutrient spatial changes of proposed EBFM after fertilizer operations comprehensively. The experiment shows that by using the proposed EBFM three years the spatial differences of soil nutrient has become narrowed. The overall fertility of soil has been increased.
Identification, Characterization, and Expression Analysis of the TaNF-YB3 Gene from Triticum aestivum
Xiuchun DONG,Zhiyuan CHENG,Shuhan CHENG,Feng XU
Notulae Botanicae Horti Agrobotanici Cluj-Napoca , 2011,
Abstract: A full-length cDNA encoding a nuclear factor-YB (NF-YB)/HAP3/CCAAT binding factor-A (CBF-A) subunit of a CCAAT-box binding complex, designated as TaNF-YB3 was isolated from Triticum aestivum. Sequence analysis indicated that the full-length cDNA was 809 bp long, including an open reading frame (ORF) of 597 bp, which encoded a deduced polypeptide of 199 amino acids and is located in chromosome 3D. The deduced protein contained conserved structural domains and showed high identity to other plant NF-YBs. TaNF-YB3 was expressed in various organs, especially in the leaves and stamens; it was also regulated by salt, mannitol, abscisic acid, wounding, and cold. Moreover, TaNF-YB3 was down-regulated by short days and vernalization, and sensitive to the transfer of day length. It was mainly induced by light and exhibited a similar diurnal rhythmic expression pattern with the CCT-domain family gene VRN2 (TaZCCT1 and TaZCCT2), but not with CO (WCO1 and TaHd1). Overall, the results suggested that TaNF-YB3, aside from having a role in regulating day length and vernalization responses, might integrate signals from other environmental stresses to perform its functions in winter wheat adaptability and development.
Matrix Metalloproteinases in Cerebral Vasospasm following Aneurysmal Subarachnoid Hemorrhage
Vivek Mehta,Jonathan Russin,Alexandra Spirtos,Shuhan He
Neurology Research International , 2013, DOI: 10.1155/2013/943761

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