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单片机系统的分时设计框架
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作者 章锐 陆国辉 《上海电机学院学报》 2005年第2期61-62,66,共3页
从CPU按“时间片”工作的基本原理出发,阐述了在监测系统中单片机控制采用分时设计的概念和思路。通过一个通用的多路数据采集框图,给出了系统设计的思想方法以及程序的基本流程和模块,并对多路数据在系统中的处理方法作了较详细的说明。
关键词 单片处理机 数据采集 分时设计 时间片 路任务
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Algorithms for semi on-line multiprocessor scheduling problems 被引量:8
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作者 杨启帆 谈之奕 +1 位作者 姚恩瑜 何勇 《Journal of Zhejiang University Science》 CSCD 2002年第1期60-64,共5页
In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but someh... In the classical multiprocessor scheduling problems, it is assumed that the problems are considered in off\|line or on\|line environment. But in practice, problems are often not really off\|line or on\|line but somehow in between. This means that, with respect to the on\|line problem, some further information about the tasks is available, which allows the improvement of the performance of the best possible algorithms. Problems of this class are called semi on\|line ones. The authors studied two semi on\|line multiprocessor scheduling problems, in which, the total processing time of all tasks is known in advance, or all processing times lie in a given interval. They proposed approximation algorithms for minimizing the makespan and analyzed their performance guarantee. The algorithms improve the known results for 3 or more processor cases in the literature. 展开更多
关键词 analysis of algorithm on\|line scheduling worst\|case ratio
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Modeling a magneto-rheological soft starter for use with belt conveyors 被引量:2
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作者 Tian Zuzhi Hou Youfu 《International Journal of Mining Science and Technology》 SCIE EI 2012年第3期385-389,共5页
The theory of magnetic circuit design, the constitutive equations of a magneto-theological fluid, and the load properties of belt conveyors were used to design a magneto-rheological soft starter test-bed. The magnetic... The theory of magnetic circuit design, the constitutive equations of a magneto-theological fluid, and the load properties of belt conveyors were used to design a magneto-rheological soft starter test-bed. The magnetic field distribution in the working gap was analyzed and the current-speed relationship was investigated. A mathematical model for the time response was deduced. The results show that a linear relationship between current and magnetic field is seen when the magnetic materials are not saturated and the magnetic field is uniform in the working section. The rotation speed of the driven shaft changes linearly with increasing time. The response is rapid and can be as short as milliseconds. This meets the starting requirements of belt conveyors. 展开更多
关键词 Magneto-theological softer starterBelt conveyorsControl modelTime response
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New composite grouting materials:Modified urea-formaldehyde resin with cement 被引量:22
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作者 Duan Hongfei Jiang Zhenquan +2 位作者 Zhu Shuyun Yao Pu Sun Qiang 《International Journal of Mining Science and Technology》 2012年第2期195-200,共6页
A new composite two component grout comprised of modified urea-formaldehyde resin and cement was formulated to take account of the advantages and disadvantages of both the cement grout and the chem- ical grout. The ne... A new composite two component grout comprised of modified urea-formaldehyde resin and cement was formulated to take account of the advantages and disadvantages of both the cement grout and the chem- ical grout. The new grout is designed for water blocking by reinforcing as well as seepage control by bore grouting. The A component consists of a modified urea-formaldehyde resin A component, some cement, and some water. The B component is an alkaline coagulant. An orthogonal test of four factors at three lev- els showed that gel time increased with increased water content and with urea-formaldehyde resin con- tent. Gel time decreased at increased levels of alkaline coagulant. The A component of this new composite grout is stable over time. A mixed cross-over test showed that as the volume ratio of A to B increases the gel time falls at first but then increases. The solid strength decreases with increasing levels of the B com- ponent. The solid strength increases over time and becomes stable by the 28th day after mixing. The vis- cosity increases with increasing levels of resin A component. The increase is exponential and may be fit to: μ = 8.162e0.0286x. 展开更多
关键词 Modified urea-formaldehyde resin A liquidGrouting materialsOrthogonal testGel timeSolidification strength
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Recent Advances in ^(19)Fluorine Magnetic Resonance Imaging with Perfluorocarbon Emulsions 被引量:2
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作者 Anne H.Schmieder Shelton D.Caruthers +2 位作者 Jochen Keupp Samuel A.Wickline Gregory M.Lanza 《Engineering》 SCIE EI 2015年第4期475-489,共15页
The research roots of 19fluorine (19F) magnetic resonance imaging (MRI) date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imagi... The research roots of 19fluorine (19F) magnetic resonance imaging (MRI) date back over 35 years. Over that time span, 1H imaging flourished and was adopted worldwide with an endless array of applications and imaging approaches, making magnetic resonance an indispensable pillar of biomedical diagnostic imaging. For many years during this timeframe, 19F imaging research continued at a slow pace as the various attributes of the technique were explored. However, over the last decade and particularly the last several years, the pace and clinical relevance of 19F imaging has exploded. In part, this is due to advances in MRI instrumentation, ~gF/1H coil designs, and ultrafast pulse sequence development for both preclinical and clinical scanners. These achievements, coupled with interest in the molecular imaging of anatomy and physiology, and combined with a cadre of innovative agents, have brought the concept of ~gF into early clinical evaluation. In this review, we attempt to provide a slice of this rich history of research and development, with a particular focus on liquid perfluorocarbon compound-based agents. 展开更多
关键词 FLUORINE magnetic resonance imaging (MRI) dual-tuned coil PERFLUOROCARBON ANGIOGENESIS cell labeling
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Pattern Specialization Based on Partial Evaluation
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作者 毛宏燕 黄林鹏 李明禄 《Journal of Shanghai Jiaotong university(Science)》 EI 2007年第5期633-638,共6页
Design pattern enables software architecture generality and reusability, but which depresses the high performance. The pattern specialization was built on partial evaluation technology to reduce the overheads of desig... Design pattern enables software architecture generality and reusability, but which depresses the high performance. The pattern specialization was built on partial evaluation technology to reduce the overheads of design pattern. The design patterns were classified to extract the common features, and the corresponding pattern specializations were constructed. In the pattern specialization, the optimization opportunities were identified, and the specialization methods and conditions were described. The syntax of binding time analysis was defined, and the semantic depicted the invariant of usage context. The virtual invocation and dispatch were eliminated, which enhances the running efficiency. This pattern specialization is a high-level specialization for improving the performance of software aimed at design level that is orthogonal with the low-level code optimization. 展开更多
关键词 design pattern pattern specialization partial evaluation specialization declaration binding time analysis
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Analysis and research on the demands of the fashion emotional design for the modem professional women
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作者 HU Chenyuan 《International English Education Research》 2016年第12期1-2,共2页
Clothing is a kind of the clothing design activity based on the emotional factors and the concrete understandings. Clothing is not only a kind of the life necessities, but also the interpretation and expression of our... Clothing is a kind of the clothing design activity based on the emotional factors and the concrete understandings. Clothing is not only a kind of the life necessities, but also the interpretation and expression of our own temperament and personalities. Of course, the best effects of the entire costume design activity can be achieved only when the costume itself is matched with the person's identity. In this paper, from the analysis of the influence and the relationship between the clothing emotion and the fashion design activities, combined with the analysis of the specific characteristics of the groups of the modern occupational females, the author explores the modem women's specific needs in the clothing emotional design, and explores the specific ideas of the modern professional women's clothing emotional design. 展开更多
关键词 Modem professional women fashion emotion design requirements connotation analysis research ideas
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Design and Implementation of Image Encryption Method by Using Chaotic Mapping Based on Multi-layer Parameter Disturbance
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作者 Zhang Shujuan He Yun 《International Journal of Technology Management》 2013年第2期11-14,共4页
Bit-plane decomposition makes images obtain a number of layers. According to the amount of data information, images are encrypted, and the paper proposes image encryption method with Chaotic Mapping based on multi-lay... Bit-plane decomposition makes images obtain a number of layers. According to the amount of data information, images are encrypted, and the paper proposes image encryption method with Chaotic Mapping based on multi-layer parameter disturbance. The advantage of multi-layer parameter disturbance is that it not only scrambles pixel location of images, but also changes pixel values of images. Bit-plane decomposition can increase the space of key. And using chaotic sequence generated by chaotic system with different complexities to encrypt layers with different information content can save operation time. The simulation experiments show that using chaotic mapping in image encryption method based on multi-layer parameter disturbance can cover plaintext effectively and safely, which makes it achieve ideal encryption effect. 展开更多
关键词 bit-plane decomposition image encryption chaotic mapping multi-layer parameter disturbance
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Nonlinear Seismic Response of Steel Concentrically Braced Frames Using Endurance Time Analysis Method
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作者 Mohammad Amin Hariri Ardebili Yashar Zarringhalam Masoud Mirtaheri Mahmood Yahyai 《Journal of Civil Engineering and Architecture》 2011年第9期847-855,共9页
In present paper application of Endurance Time Analysis (ETA) method in nonlinear seismic assessment of steel concentrically braced frames is studied. In this method structure is subjected to a set of predesigned in... In present paper application of Endurance Time Analysis (ETA) method in nonlinear seismic assessment of steel concentrically braced frames is studied. In this method structure is subjected to a set of predesigned increasing acceleration functions and various responses of the structure are recorded during synthetic seismic excitation. The averages of maximum values for various responses in Nonlinear Time-History Analyses (NTHA) extracted from real ground motions are expected to be close to those obtained from ETA up to equivalent target time. For this purpose a set of 9, 11, 13 and 15 stories steel frames were designed and plastic hinge method was selected as source of nonlinearity in all cases. Responses were compared based on interstory drift ratio and story shear in two methods and results show satisfactory consistency between two methods. Finally, it was concluded that the ETA method can be used as alternative method in nonlinear seismic analysis of concentrically braced steel frames. 展开更多
关键词 Endurance time analysis concentrically braced frames nonlinear seismic assessment.
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Engineering practice of seismic isolation and energy dissipation structures in China 被引量:10
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作者 PAN Peng YE LiePing +1 位作者 SHI Wei CAO HaiYun 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第11期3036-3046,共11页
The concepts of seismic isolation and energy dissipation structures emerged in the early 1970s.In China,the first seismic isolation structure was finished in 1993,and the first energy dissipation structure was built a... The concepts of seismic isolation and energy dissipation structures emerged in the early 1970s.In China,the first seismic isolation structure was finished in 1993,and the first energy dissipation structure was built at about the same time.Up to 2007,China had more than 600 seismic isolation and about 100 energy dissipation building structures.In 2008,the huge Wenchuan earthquake hit the southwest of China,which triggered a bloom of new seismic isolation and energy dissipation structures.This paper presents the development history and representative applications of seismic isolation and energy dissipation structures in China,reviews the state-of-the-practice of Chinese design,and discusses the challenges in the future applications.Major findings are as follows:Basic design procedures are becoming standardized after more than ten years of experiences,which mainly involve determination of design earthquake forces,selection of ground motions,modeling and time-history analyses,and performance criteria.Nonlinear time-history analyses using multiple ground motions are the characteristic of the design of seismic isolation and energy dissipation structures.Regulations,standardization and quality control of devices,balance between performance and cost,comparison with real responses,and regular inspection are identified as the issues that should be improved to further promote the application of seismic isolation and energy dissipation structures in China. 展开更多
关键词 seismic isolation structure energy dissipation structure development history design practice regulatory environment
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Influence of solar wind dynamic pressure on geomagnetic Dst index during various magnetic storms 被引量:10
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作者 ZHAO Hong ZONG QiuGang +1 位作者 WEI Yong WANG YongFu 《Science China(Technological Sciences)》 SCIE EI CAS 2011年第6期1445-1454,共10页
The Dst index,designed as a proxy of ring current intensity,is known to be also affected by other magnetospheric current systems,e.g.magnetopause current.The pressure-corrected Dst index is obtained by removing the ef... The Dst index,designed as a proxy of ring current intensity,is known to be also affected by other magnetospheric current systems,e.g.magnetopause current.The pressure-corrected Dst index is obtained by removing the effects of the solar wind dynamic pressure and the quiet time ring current.However,all previous studies treated the correction coefficient as an averaged parameter for storms of different intensity.In this paper,based on the Burton's equations and employing two independent methods,we will show a positive correlation between pressure-correction coefficient b and the intensity of the storms.We divided our storm database(872 storms in total) into three categories according to the intensity of storms.In order to improve the accuracy of calculating,we also used the higher-resolution SYM-H index data instead of Dst index to compute the corrected Dst index during different storms.Furthermore,we are able to provide corrected magnetic storm index with high-time resolution(-1 min). 展开更多
关键词 corrected Dst index pressure correction geomagnetic storms with different intensity
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Design of ultra-compact wavelength splitter based on lithium niobate nanowire optical waveguides 被引量:2
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作者 陈明 刘子晨 《Optoelectronics Letters》 EI 2012年第1期17-20,共4页
A wavelength splitter with ultra-compact and simple structure is proposed and analyzed by using both plane wave expansion (PWE) method and finite difference time domain (FDTD) method. The device is based on direct... A wavelength splitter with ultra-compact and simple structure is proposed and analyzed by using both plane wave expansion (PWE) method and finite difference time domain (FDTD) method. The device is based on directional coupling between two parallel lithium niobate (LiNbO3, LN) nanowire optical waveguides. The wavelength splitter with a coupling region length of 5 um can separate 1.3 um and 1.55 um wavelengths for corresponding outputs with transmittance higher than 97%. 展开更多
关键词 Finite difference time domain method NANOWIRES
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Design of Optical Logic Gates Using Self-collimated Beams in 2D Photonic Crystal 被引量:1
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作者 X. Susan CHRISTINA A. R KABILAN 《Photonic Sensors》 SCIE EI CAS 2012年第2期173-179,共7页
Optical logic gates are elementary components for optical network and optical computing. In this paper, we propose a structure for AND, NAND, XNOR and NOR logic gates in the two dimensional photonic crystal which util... Optical logic gates are elementary components for optical network and optical computing. In this paper, we propose a structure for AND, NAND, XNOR and NOR logic gates in the two dimensional photonic crystal which utilizes the dispersion based self-collimation effect. The self-collimated beam is splitted by the line defect and interfered with other self-collimated beam. This interference may be constructive or destructive based on their phase difference. This phenomenon is employed to realize all-optical logic gates. The gates are demonstrated numerically by computing electromagnetic field distribution using the finite difference time domain (FDTD) method. The results ensure that this design can function as AND, NAND, XNOR and NOR logic gates. The size of the structure is about 10 μm× 10 μm which in turn results in an increase in the speed and all the gates are realized in the same configuration. The ON-OFF contrast ratio is about 6 dB. 展开更多
关键词 Optical computing photonic crystal band diagram equifrequency contour all-optical logic gates
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A multi-modular shunt active power filter system and its novel fault-tolerant strategy based on split-phase control and real-time bus communication
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作者 Qun-wei XU Jin-xiang ZHAN +1 位作者 Long XIAO Guo-zhu CHEN 《Frontiers of Information Technology & Electronic Engineering》 SCIE EI CSCD 2018年第9期1166-1179,共14页
We first present a new multi-modular shunt active power filter system suitable for large-capacity compensation. Each module in the system has the same circuit topology, system functionality, and controller design, to ... We first present a new multi-modular shunt active power filter system suitable for large-capacity compensation. Each module in the system has the same circuit topology, system functionality, and controller design, to achieve coordination control among the modules. The module's reference signals are obtained by multiplying the total reference signal by the respective distribution coefficient. Next, a novel fault-tolerant approach is proposed based on split-phase control in the a-b-c frame and real-time bus communication. When a phase fault occurs, instead of halting the whole module, the proposed strategy isolates only the faulted bridge arm, and then recalculates the distribution coefficients and transfers the compensation capacity to the same phases of the other normal modules, resulting in a continuous operation of the faulted module and optimization of the remaining usable power devices. Through steady-state analysis of the post-fault circuit, the system stability and control reliability are proven to be high enough to guarantee its engineering application value. Finally, a prototype is established and experimental results show the validity and feasibility of the proposed multi-modular system and its fault-tolerant control strategy. 展开更多
关键词 Shunt active power filter Fault-tolerant topology Split-phase control Bus communication
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Design and Fabrication of a Novel Core-Suspended Optic Fiber for Distributed Gas Sensor 被引量:1
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作者 Tao ZHANG 《Photonic Sensors》 SCIE EI CAS 2014年第2期97-101,共5页
We designed a novel core-suspended capillary fiber that the core was suspended in the air hole and close to the inner surface of the capillary, and experimentally demonstrated its fabrication technology. In addition, ... We designed a novel core-suspended capillary fiber that the core was suspended in the air hole and close to the inner surface of the capillary, and experimentally demonstrated its fabrication technology. In addition, a method for linking a single mode fiber and a core-suspended fiber was proposed based on splicing and tapering at the fusion point between the two fibers. By combining with the optical time domain reflectometer technology, we constructed a distributed gas sensor system to monitor greenhouse gas based on this novel fiber. 展开更多
关键词 Hollow fiber core-suspended LINKING distributed gas sensor
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