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液体弹性波技术演进及其应用前景研析 被引量:2
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作者 陈李斌 党伟 《华北石油设计》 2002年第1期4-6,共3页
文章介绍了液体弹性波技术的基本特征,技术背景及演进过程,并对该技术在石油工业中的应用前景进行了探讨。
关键词 液体弹性波 石油工业 原油输送工艺 管流控制 应用前景
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Study on Management and Control of Nonpoint Source Pollution from Urban Surface Runoff 被引量:2
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作者 Chen Keliang Zhu Xiaodong Wang Xianghua Ma Yan 《Chinese Journal of Population,Resources and Environment》 北大核心 2007年第1期39-44,共6页
Urbanization is the dominant form of land-use change in terms of impacts on water quality, hydrology, physical proper- ties of watersheds and their nonpoint source (NPS) pollution po- tential at present. Urbanization ... Urbanization is the dominant form of land-use change in terms of impacts on water quality, hydrology, physical proper- ties of watersheds and their nonpoint source (NPS) pollution po- tential at present. Urbanization has changed the source, process and sink of urban NPS pollution, especially raised the pollution load of urban runoff NPS in receiving water. Urban runoff pollu- tion is a hot spot of research on NPS. This paper analyzed type, source and harm of the NPS pollutants of urban runoff and its influence on the receiving water. Through estimating NPS pollu- tion load of urban runoff and summarizing the law and character- istics of urban runoff NPS systemically, study on management and control of urban runoff NPS pollution was focused on the applica- tion of BMPs (best management practices). It is a fresh method- ology that management and control on NPS pollution from urban surface runoff was analyzed by methods of landscape ecology, environmental economics and environmental management. The paper provided a scientific reference for mitigating urban water environment pressure and an effective method for management and control of NPS pollution from urban surface runoff.. 展开更多
关键词 urban surface runoff nonpoint source pollution MANAGEMENT CONTROL
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Thyristor Controlled Phase Shifter:A Comprehensive Survey
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作者 那吉.阿哈姆斯 陈珩 《Journal of Southeast University(English Edition)》 EI CAS 2001年第1期85-88,共4页
Thyristor control phase shifter (TCPS) is one of the new facilities implemented in power network, leading to the development of economically efficient and technically reliable system. This paper introduces the functio... Thyristor control phase shifter (TCPS) is one of the new facilities implemented in power network, leading to the development of economically efficient and technically reliable system. This paper introduces the function of TCPS in power system, describes its working principle and structure, and suggests some simple models used in its study and briefly presents the comparison between different types of TCPSs and their applications. 展开更多
关键词 power system FACTS TCPS phase angle regulation
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Application of pH control to a tubular flow reactor
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作者 .Halil Vural Ayla Altinten +2 位作者 Hale Hapoglu Sebahat Erdogan Mustafa Alpbaz 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2015年第1期154-161,共8页
Tubular flow reactors are mainly used in chemical industry and waste water discharged units. Control of output variables is very difficult because of the existence of high dead-time in these types of reactors. In the ... Tubular flow reactors are mainly used in chemical industry and waste water discharged units. Control of output variables is very difficult because of the existence of high dead-time in these types of reactors. In the present work, sodium hydroxide and acetic acid solutions were sent to the tubular flow reactor. The aim was to control p H at 7 in the nonlinear region. The p H control of a tubular flow reactor with high time delay and a highly nonlinear behavior in p H neutralization reaction was investigated experimentally in the face of the various load and set point changes. Firstly, efficiency of conventional Proportional-Integral-Derivative(PID) algorithm in the experiments was tested. Then self-tuning PID(STPID) control system was applied by using the ARMAX model. The model parameters were calculated from input–output data by using PRBS signal as disturbance and Bierman algorithm. Lastly, the experimental fuzzy control of p H based on fuzzy model was achieved to compare the success of fuzzy approach with the performance of other control cases studied. 展开更多
关键词 Tubular flow reactor p H control Self tuning PID control PID control Fuzzy control
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A novel design of power management integrated circuit with 90 plus efficiency used in AC/DC converter
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作者 Jiang Yanfeng 《Engineering Sciences》 EI 2010年第1期53-58,共6页
Recently, resonant AC/DC converter has been accepted by the industry. However, the efficiency will be decreased at light load. So, a novel topology with critical controlling mode combined with resonant ones is propose... Recently, resonant AC/DC converter has been accepted by the industry. However, the efficiency will be decreased at light load. So, a novel topology with critical controlling mode combined with resonant ones is proposed in this paper. The new topology can correspond to a 90 plus percent of power converting. So,a novel topology of an state of art integrated circuit, which can be used as power management circuit, has been designed based on the above new topology. A simulator which is specifically suitable for the power controller has been founded in this work and it has been used for the simulation of the novel architecture and the proposed integrated circuit. 展开更多
关键词 power management integrated circuit CONVERTER RESONANCE
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Proximal and distal esophageal sensitivity is decreased in patients with Barrett’s esophagus
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作者 Anne L Kraru Sφren S Olesen +2 位作者 Peter Funch-Jensen Hans Gregersen Asbjφrn M Drewes 《World Journal of Gastroenterology》 SCIE CAS CSCD 2011年第4期514-521,共8页
AIM: To investigate sensations to multimodal pain stimulation in the metaplastic and normal parts of the esophagus in patients with Barrett’s esophagus (BE). METHODS: Fifteen patients with BE and 15 age-matched healt... AIM: To investigate sensations to multimodal pain stimulation in the metaplastic and normal parts of the esophagus in patients with Barrett’s esophagus (BE). METHODS: Fifteen patients with BE and 15 age-matched healthy volunteers were subjected to mechanical, thermal and electrical pain stimuli of the esophagus. Both the metaplastic part and the normal part (4 and 14 cm, respectively, above the esophago-gastric junction) were examined. At sensory thresholds the stimulation intensity, referred pain areas, and evoked brain potentials were recorded. RESULTS: Patients were hyposensitive to heat stimulation both in the metaplastic part [median stimulation time to reach the pain detection threshold: 15 (12-34) s vs 14 (6-23) s in controls; F = 4.5, P = 0.04] and the normal part of the esophagus [median 17 (6-32) s vs 13 (8-20) s in controls; F = 6.2, P = 0.02]. Furthermore, patients were hyposensitive in the metaplastic part of the esophagus to mechanical distension [median volume at moderate pain: 50 (20-50) mL vs 33 (13-50) mL in controls; F = 5.7, P = 0.02]. No indication of central nervous system abnormalities was present, as responses were comparable between groups to electrical pain stimuli in the metaplastic part [median current evoking moderate pain: 13 (6-26) mA vs 12 (9-24) mA in controls; F = 0.1, P = 0.7], and in the normal part of the esophagus [median current evoking moderate pain: 9 (6-16) mA, vs 11 (5-11) mA in controls; F = 3.4, P = 0.07]. Furthermore, no differences were seen for the referred pain areas (P-values all > 0.3) or latencies and amplitudes for the evoked brain potentials (P-values all > 0.1). CONCLUSION: Patients with BE are hyposensitive both in the metaplastic and normal part of esophagus likely as a result of abnormalities affecting peripheral nerve pathways. 展开更多
关键词 Barrett’s esophagus Heat Multimodal PAIN Sensitivity
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Information System Functions for SmartGrid Management
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作者 Mila llieva-Obretenova 《Sociology Study》 2016年第2期96-103,共8页
The violently penetration of renewables in power supply network leads to situations, by which the offer exceeds the demand. Therefore, it is necessary to include a system for processes' management. SmartGrid is a pla... The violently penetration of renewables in power supply network leads to situations, by which the offer exceeds the demand. Therefore, it is necessary to include a system for processes' management. SmartGrid is a platform over the power supply network. It is represented with its network and services, which also have to be managed. The paper aims to show the second stage of SmartGrid management modeling. It meets heterogeneous requirements of the actors--subscriber without photovoltaics, subscriber with photovoltaics, service provider, network operator, and network elements operator--to service and network management and is oriented to functional areas, covering the life cycle of power supply service: Design, Planning, Installation, Provision, Configuration, Maintenance, Performance, Accounting, Buying Up, Security and Subscriber Control. Functional models for existing networks--telecommunications--are used and they are adapted to power supply. The results are illustrated with three functional areas for service management: Accounting, Buying Up, and Performance. The synthesis of network management functions and network element management functions are similar. 展开更多
关键词 SmartGrid functional areas service management network management network element management
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Hybrid Operation of Fault Current Limiter and Thyristor Controlled Braking Resistor 被引量:1
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作者 Masaki Yagami Junji Tamura 《Journal of Energy and Power Engineering》 2012年第4期601-608,共8页
The effectiveness of a combination of fault current limiter and thyristor controlled braking resistor on power system stability enhancement and damping turbine shaft torsional oscillations has been studied. If both de... The effectiveness of a combination of fault current limiter and thyristor controlled braking resistor on power system stability enhancement and damping turbine shaft torsional oscillations has been studied. If both devices operate at the same bus, the stabilization control scheme can be carried out continuously and with flexibility. As a result, the fault currents are limited, and the generator disturbances and the turbine shaft torsional oscillations are converged quickly. In this paper, the effectiveness of the combination of both devices has been demonstrated by considering 3LG (three-lines-to-ground) fault in a two-machine infinite bus system. Also, temperature rise effect of both devices with various resistance values and weights has been demonstrated. Simulation results indicate a significant power system stability enhancement and damping turbine shaft torsional oscillations as well as with allowable temperature rise. 展开更多
关键词 Fault current limiter thyristor controlled braking resistor fault current power system stability turbine shaft torsional oscillation temperature rise effect.
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Study on asymmetric interior corner flow in microgravity condition 被引量:3
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作者 LI JingHao CHEN XiaoQian +1 位作者 HUANG YiYong BAI YuZhu 《Science China(Technological Sciences)》 SCIE EI CAS 2012年第8期2332-2337,共6页
The capillary flow in asymmetric interior corner consisting of straight vane and curved wall is studied with analytical solution.The concept of equivalent interior corner angle is proposed to convert the asymmetric in... The capillary flow in asymmetric interior corner consisting of straight vane and curved wall is studied with analytical solution.The concept of equivalent interior corner angle is proposed to convert the asymmetric interior corner model into symmetric interior corner model.Then the governing equations of interior corner flow are established,and based on which the interior corner flow is calculated.This method is used to analyze the capillary flow in cylindrical vane-type surface tension tank with outer vanes.The research can provide beneficial reference to the design of vane-type surface tension tank. 展开更多
关键词 asymmetric interior corner flow equivalent interior corner angle vane-type surface tension tank analytical solution
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Conflict detection and resolution for authorization policies in workflow systems 被引量:1
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作者 Chen-hua MA Guo-dong LU Jiong QIU 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2009年第8期1082-1092,共11页
The specification of authorization policies in access control models proposed so far cannot satisfy the requirements in workflow management systems(WFMSs).Furthermore,existing approaches have not provided effective co... The specification of authorization policies in access control models proposed so far cannot satisfy the requirements in workflow management systems(WFMSs).Furthermore,existing approaches have not provided effective conflict detection and resolution methods to maintain the consistency of authorization polices in WFMSs.To address these concerns,we propose the definition of authorization policies in which context constraints are considered and the complicated requirements in WFMSs can be satisfied.Based on the definition,we put forward static and dynamic conflict detection methods for authorization policies.By defining two new concepts,the precedence establishment rule and the conflict resolution policy,we provide a flexible approach to resolving conflicts. 展开更多
关键词 Workflow management system (WFMS) Authorization policy Conflict detection and resolution
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An optimal control model of mosquito reduction management in a dengue endemic region
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作者 Karunia Putra Wijaya Thomas Gotz Edy Soewono 《International Journal of Biomathematics》 2014年第5期145-166,共22页
Aedes aegypti is known as the responsible vector in transmitting dengue flavivirus. Unavailability of medication to cure the transmission in human blood becomes a global health issue in recent decades. World epidemiol... Aedes aegypti is known as the responsible vector in transmitting dengue flavivirus. Unavailability of medication to cure the transmission in human blood becomes a global health issue in recent decades. World epidemiologists are encouraged to focus on investigation toward an effective and inexpensive way to prevent dengue transmission, i.e. mosquito control. In this paper, we present a model depicting the dynamics of mosquito population based on indoor-outdoor life cycle classification. The basic mosquito offspring number is obtained and analysis of equilibria is shown. We bring along a discussion on application of optimal control model which engineers two simultaneous schemes. The first scheme is done by disseminating chemical like Temephos in spots where eggs and larvae develop, meanwhile the second scheme is done by conducting fumigation through areas where adult mosquitoes prevalently nest, indoor as well as outdoor. A version of gradient-based method is presented to set down a workflow in minimizing the objective functional with respect to control variable. Numerical results from analysis of the basic mosquito offspring number with constant control and from optimal control suggest that one has to enhance the usage of fumigation rather than Temephos. It is also suggested that applying both control schemes simultaneously gives the most significant reduction to the population. 展开更多
关键词 Mosquito population dynamics mosquito reduction management the basicmosquito offspring number optimal control.
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