逆磁性 的英文怎麼說

中文拼音 [nìcíxìng]
逆磁性 英文
diamagnetism
  • 逆 : Ⅰ形容詞1 （方向相反） contrary; counter 2 [數學] inverse; converse Ⅱ動詞1 （抵觸; 不順從） go aga...
  • 磁 : 名詞1. [物理學] （磁性; 能吸引鐵、鎳等的性質） magnetism 2. （瓷） porcelain; china
  • 性 : Ⅰ名詞1 （性格） nature; character; disposition 2 （性能; 性質） property; quality 3 （性別） sex ...
  • 磁性 : [物理學] magnetism; magnetic; magnetic performance; magnetic property
  1. Many of the metals and most of the nonmetals are diamagnetic.

    許多金屬和大部分非金屬都是逆磁性的。
  2. The modulating signals of firing delay angle at the rectifier and firing lead angle at the inverter, and the excitation voltage are chosen to be control variables. the offset of the current of dc line and the extinction angle and the power angle of generator are chosen to be control outputs. then a nonlinear controller is designed for the system under study according to direct feedback linearization theory

    以整流側觸發延遲角的調節信號、逆變側觸發超前角的調節信號以及發電機勵磁電壓作為控制變量，以直流線路電流、逆變側關斷角以及發電機功角的偏移量作為目標輸出，用直接反饋線性化方法設計了系統的非線性控制器。
  3. With soft - switching technology, inverter spot - welding power source has lower switching dissipation, lower electromagnetic interference and lower sensitivity to parasitic parameters of power circuit, contribute to inverter output characteristics and circuit efficiency, stability and reliability

    採用軟開關技術的點焊逆變電源，可減小開關損耗、電磁干擾及對電路寄生參數的敏感性，並從根本上改善電路的輸出特性，提高電路的效率、穩定性和可靠性。
  4. First, in virtual of identification of flaws is a typical of in - verse problems, proceeding from time - harmonic electromagnetic maxwell ' s equa - tion and helmholtz equation, the uniqueness and existence of direct scattering problems including the numerical algorithms of diverse of boundary conditions is given. second, the uniqueness and existence of inverse scattering problems and the theory of ill - posed integral equation are briefly looked back upon. finally, indicator function method for boundary identification is set up under all kinds of boundary conditions for inverse scattering of homogenous and inhomogenous objects, meanwhile, the proof of possibility for near - field measurements and nu - merical simulation are given

    由於缺陷的識別是一類典型的反問題，因而首先從時諧電磁maxwell方程和helmholz方程出發，具體地闡述了求解正散射問題的有關方法，包括各種（夾雜）邊界條件下的數值解法，就解的存在性唯一性給予了肯定的回答；隨后對逆散射問題的理論作了簡短的回顧，包括解的唯一性以及非線性不適定積分方程的處理等；然後對均勻介質和非均勻介質的逆散射問題建立了在各種邊界條件下的邊界識別的指示函數方法，鑒于近場數據獲得的重要性，對近場測試時邊界識別的方法給予了相應的證明，並且實現了數值模擬。
  5. The auxiliary modulating signals of the current controller at the rectifier and the extinction angle controller at the inverter, and the reference voltage of exciter are chosen to be control variables. then the all - state feedback linear optimal controller is designed

    以直流系統整流側電流控制器的輔助調節信號、逆變側關斷角控制器的輔助調節信號以及勵磁系統參考電壓作為控制變量，設計了系統的全狀態反饋線性最優控制器。
  6. The stability of electric power system has been being focused for a long time toprevent a power system from losing synchronism after sudden fault ， researchers have done much work and got many accomplishments this paper applied the direct feedback linearization ( dfl ) technique on the power system ， a strong nonlinear system simulation results by matlab proved this method efficiency main works and results are as follows ： this paper compared some existing methods in excitation control ， fast valve control and coordinated control respectively, analyzed the developments and actuality of nonlinear control research in brief, illustrated why ransient stability could be greatly improved by using the fast valve control in chapter 3 ， indicated the importance of coordinated control farther this paper introduced the inverse system theory, based on which ， discussed the dfl theory, pointed out which had consistency with the inverse theory, expanded the dfl theory combined the idiographic model equations ， made which adapt to the model of a single machine - infinite bus power system this paper referenced abundance articles and educed a set of equations ， which could describe the dynamical process of excitation and fast valve control for synchronous generators in the equations ， there were several very important parameters of power system - - rotor angle ( ) ， rotor speed ( ) ， generator q axis voltage ( eq ) ， transient voltage ( e ' q ) ， active power ( pe ) ， mechanical input power ( pm ) ， valve opening ( ) ， generator terminal voltage ( vt ) ， based on the model ， nonlinear coordinated controller and terminal voltage optimal controller have been designed by using the expanded dfl theory and lq optimal control theory the simulation results showed that the controller could keep power system transiently stable under the effects of a symmetrical 3 - phase short circuit fault ， which achieved better postfault regulation compared with another two routine methods ， one is the proportion excitation controller and proportion fast valve controller, the other is the proportion excitation controller and the optimal fast valve controller, which could exert good performance when met 1ittle disturbance either

    在介紹逆系統理論的基礎上，詳細介紹了dfl理論，通過比較闡明了dfl理論其本質是逆系統方法的一類，並結合具體課題推導出的模型方程將dfl理論進行了擴展，使之適應于電力系統這個強非線性對象。通過參考大量的書籍文獻推導出一套實用的可將大型汽輪發電機勵磁與汽門綜合起來進行控制的模型方程，此模型方程涵蓋了電力系統中特別引人注目的幾個量- -轉子角、轉子轉速、發電機q軸電勢eq 、暫態電勢e ' q 、有功功率pe 、機械功率pm 、汽門開度、機端電壓vt ，在此基礎上建立了實用的電力系統簡化的數學模型，並將擴展的dfl理論應用於此模型系統，結合線性二次型最優控制理論設計出大型汽輪發電機的非線性綜合控制器及機端電壓最優控制器，通過模擬實驗與採用常規的按電壓偏差進行調節的比例式勵磁控制器+汽門比例控制及採用常規的按電壓偏差進行調節的比例式勵磁調節器和基於二次型性能指標設計的最優快控汽門（考慮發電機的飽和因素）進行了對比，證實了採用此種控制器可以有效地提高電力系統的暫態穩定性，並且在電力系統遭受小干擾時同樣具有良好的調節性能。
  7. Magnetic field polarity reversals are magnetic poleshifts

    磁場極性逆轉就是磁極轉換。
  8. There are five parts are as follows : in part one, the concept of switching function is introduced first to establish the nonlinear mathematical model of the induction motor variable frequency speed adjustment system which is fed by a sine pulse width modulated ( spwm ) inverter and takes the effect of the main magnetic circuit saturation into consideration, then the low frequency oscillation of the system is simulated according to the model. next, from the view point of energy conversion of the inverter - induction system, a criterion for the low frequency oscillation is proposed to determine whether the system is in low frequency oscillation which is judged by whether the interval of the negative current component of the inverter input current is more than 1 / fc ( fc is the carrier wave frequency of the inverter ) or not

    首先引入開關函數概念，建立了正弦脈寬調制（ spwm ）逆變器供電異步電動機，考慮主磁路飽和時的變頻調速系統整體數學模型，模擬系統的低頻振蕩；其次從逆變器-異步電動機系統能量轉換角度出發，提出通過檢測逆變器輸入電流中負電流的間隔時間是否大於1 / f _ c （ f _ c為逆變器載波頻率）來判定系統是否出現低頻振蕩；最後的實驗結果驗證了系統低頻振蕩建模和判據的實用性和正確性。
  9. A reversal could knock out power grids, hurt astronauts and satellites, widen atmospheric ozone holes, send polar auroras flashing to the equator and confuse birds, fish and migratory animals that rely on the steadiness of the magnetic field as a navigation aid

    逆轉會破壞能量網格，損害宇航員和衛星，加大臭氧層空洞，發送極光到赤道而搞亂鳥類，魚和遷徙動物，它們依靠磁場的穩定性作為導航幫助。
  10. The relating to methods based on the research on international and domestic electromagnetic wave ( elastic wave, acoustic wave ) for the identification of flaws are all - round viewed

    本文對國際和國內基於電磁波（聲波，彈性波）逆散射理論研究缺陷識別的有關方法給予了全面的評述。
  11. Abstract : a new current feedback control method of brushless dc motor ( bldcm ) is introduced in this paper, which combines the traditional overlap method with the fixed - frequency sampling current control method. it both stabilizes the work frequency of the inverter, and improves the commutative performance of bldcm. and it is verified by the result of the simulation

    文摘:提出一種永磁無刷直流電機電流反饋新的控制方法，即採用常規重疊換相法與定頻采樣電流控制相結合的方法，既能穩定逆變器的工作頻率，又改善了永磁無刷直流電機的換相性能，利用模擬對提出的方法進行了驗證。
  12. This paper presents an adaptive control for the semi - active suspension using the combination of mr damper and feedback neural networks. analyzing the mr damper, a smart actuator, chapter 3 gives the design of pre - amplifier of current, which provides the external magnetic field. and it discusses the additional nonlinear stiffness resulted from the transition of mr fluid from liquid to semi - solid or solid

    在分析新型智能材料用做作動器的磁流變阻尼器特性的基礎上，本文給出阻尼器線圈的前置電流放大電路，並討論了因磁流變液體固液態之間的可逆變化而產生的懸架系附加非線性剛度。
  13. This paper considers two controllers with different feedback signals ? the ac current phase angle of converter transformer and the ac voltage magnitude of inverter bus, respectively. pscad / emtdc simulation software is used for the controller testing. the test models used for the analysis are the cigre hvdc benchmark systems with different scr at the inverter side

    為了驗證該控制方式的有效性，本文採用了電磁暫態模擬軟體pscad emtdc ，在國際大電網會議cigre提出的hvdc標準模型上，用逆變側短路比不同的系統對調制控制器的性能進行了模擬測試，調試出了調制控制器的各參數值。
  14. In many fields, such as remote sensing, nuclear medical, computer tomography, geophysical prospecting, groundwater hydrology, global ocean modeling, image processing, tumor detection, nondestructive detection, the objective of applied sciences and engineering is the recovery of the original signal given a collection of noisy observations of the original signal ; we call these problems inverse problem

    在遙感技術、核醫療技術、計算機斷層掃描（ ct ）技術、地質勘探、地下水文學、電磁輻射、圖像恢復和重構、腫瘤檢測、非破壞性檢測等科學研究和工程實踐中，經常需要根據一組觀測到的數據來估計目標的真實信號，而觀測到的數據往往是真實信號經模糊、失真和加噪等過程后所得的輸出信號，通常稱這類問題為逆問題。
  15. Specific issues examined are : compensation for the variation of the stator resistance, the offset error of the dc bus voltage, the voltage error generated by the forward voltage drop the dead time of the switches, improvement of the steady state performance, and the speed sensorless control for the pmsm dtc drive system are of major concern in this thesis

    定子電阻變化，直流母線電壓漂移，開關器件反向相電壓降、逆變器死區時間引起的電壓誤差的補償，提高系統穩態運行性能以及永磁同步電機直接轉矩控制的無速度傳感器運行方案等問題都是本文研究的重點。轉矩的快速響應是直接轉矩控制演算法的一個卓越的性能。
  16. Some research about sensorless control of induction motors in recent years has been introduced in chapter one. in chapter two, a field - oriented control system with current regulator and voltage source inverter ( vsi ) is presented firstly, which is proved in theory that the voltage feed - forward decoupler can be omitted, the good decoupled control properties of flux current and torque current is also validated by experiments with speed - sensor based on f240dsp real system

    論文第二章從異步電機的基本數學模型入手，介紹了一種基於轉子磁場定向的帶電流內環控制的電壓型逆變器輸出閉環矢量控制結構，在理論上證明了該模型可省略電壓前饋解耦環節，採用f240dsp晶元構建的帶速度傳感器實驗系統驗證了其定子電流勵磁分量和轉矩分量有良好的解耦控制特性。
  17. In dtc system, the concept of space vector is introduced to analyze and control the ac motor, the electromagnetic torque and flux are calculated and controlled in the stationary coordinate, and the optimal pwm gating signals are generated to control the inverter to acquire high dynamic torque according to the output of the bang - bang regulators

    直接轉矩控制採用空間矢量的概念來分析三相異步交流電動機的數學模型和各物理量，直接在靜止坐標系下計算與控制交流電動機轉矩和磁鏈，藉助于離散的兩點式調節產生pwm信號，直接對逆變器的開關狀態進行最佳控制，以獲得轉矩的高動態性能。
  18. Chemical - shift magnetic resonance ( mr ) imaging is gradually accepted as a useful technique to distinguish benign adrenal lesions from malignant counterparts based on in - phase and out - of - phase gradient - echo pulse sequences

    摘要化學相差磁振造影中，順相及逆相脈沖序最之腫瘤訊號強度的變化，應用在臨床上分辨腎上腺良性或惡性腺瘤是有用且逐漸被接受的圖象診斷工具。
  19. This paper studies on used the ac servo system based on ti dsp ( lf2407a ) and the foc and digital signal processing thorem, achieves following results : algorithm. we employ svpwm ( space voltage pwm ) algorithm, improve the efficiency of the electric source, and decrease the harmonious elements. we build the mathematic model of the system and simulate it on matlab platform, dsigne segmented pid regulator to adapt variable speed and widen the speed range. measurement. the velocity and electric current measuring, we adopt multi - sampling - rate and digital filter principles. as more improvements we make, the whole system gets a good results. pc control. the complete controlling system can be controlled remotely. so we develop the pc controlling program.

    採用磁場定向脈寬調制演算法，提高了電源利用率，降低了逆變電壓的諧波，改善了電機的運行特性，降低了對電網的污染；在matlab平臺上建立了交流永磁同步伺服電機和電壓空間矢量脈寬調制控制系統的數學模型，在模擬的基礎上，對傳統pid調節器進行了改進，提出轉速調節器和電流調節器採用分段pid結構，根據給定轉速所處的區間，自動選擇相應pid調節器的參數，拓寬了調速范圍，提高了控制精度。
  20. This dissertation also works into this area in relation to the design of a real system

    因此，可並聯逆變電源的電磁兼容性設計非常重要。本文結合實際對此進行了深入研究。
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