negative frequency 中文意思是什麼
negative frequency
解釋
負頻率-
In the forth chapter the series negative feedback and interstage mismatching are presentation, and a low noise amplifier whose operating frequency is 1. 5ghz 1. 8ghz is developed
第四章詳細介紹了源極串聯負反饋和級間失配法，並設計和製作了1 . 5ghz 1 . 8ghz低噪聲放大器。 -
Dds951 series electronic single - phase electric meter is the most advanced static electronic meter in china. the meter designs use large - scale intergated circuit. high reliability step motor, it can the ac single - phase active energv voltage rating : 220v : frequency 50hz, positive and negative two directions and accumulates in one direction. the test singnal is isolated by phototransistor : it also has the function of anti - fraud, and indicates it s operation situation on flash light, so it could be managed very easy
Dds951單相電子電能表，是金雀儀表公司開發的新型電度表。該產品是採用規模專用集成電路，高可靠性步進電機等先進技術製造的國內最新電能試題新產品，用來計量額定電壓為220v ，頻率為50hz的交流單相有功電能，該產品能夠精確計量正負兩方向的有功電能，且以同一個方向累計。 -
The second, at the high frequency primary coil, when switch turn on with control signal ( the spwm pulse is modulated ), in the positive or negative semi - period of low frequency modulation signal, transformer coil with same direction voltage. the magnetic flux of transformer core will increase step by step. at the end, it leads to magnetic flux saturation
二、在高頻變壓器原邊，當開關管接收控制信號脈沖列（經調制的spwm波列）導通時，在低頻調制信號的正半周或負半周內，施加在變壓器繞組上的是同一方向的電壓，變壓器磁芯中的磁通可能將級進地逐漸增加，導致磁芯飽和，造成磁偏或單向磁化，導致低頻電信號放大失真或由於很大的磁化電流而無法正常工作。 -
Torsional interaction exists between hvdc converters and turbine - generators, and negative electrical damping provided by hvdc may cause subsynchronous oscillation ( sso ) that can lead to turbine - generator shaft failure and electrical instability at oscillation frequencies lower than the fundamental system frequency
高壓直流輸電（ high - voltage - direct - current - - - - hvdc ）系統與臨近同步發電機組之間存在著扭振相互作用， hvdc的電氣負阻尼作用有可能引起機組在次同步頻率范圍的扭轉振蕩。 -
For the negative uniaxial crystal material, the principal mode is a hybrid guided mode, which can also be excited by the light at any frequency, but when the single mode propagation condition can not be satisfied, some of the higher order hybrid guided modes will exist in the waveguide
對于負單軸晶體，波導的主模是混合模hgm _ 0模，該模式同樣可被任何頻率的光波所激勵；當光波波長滿足一定條件時，波導內傳輸單模，否則，將激勵起高階混合模。 -
The most achievement is that we firstly obtain the analytic accurate solution of the modal fields of the waveguide structure and find some available character : ( 1 ) the different uniaxial crystal materials have the different propagation properties ; ( 2 ) when the optical axis of the crystal is on the plane that is made up of the normal direction of the waveguide plane and the propagation, there are te mode and tm mode in this special waveguide, but the principal mode is different of the character of the uniaxial crystal, the principal mode is the principal mode of te mode for the negative uniaxial crystal, but the one of tm mode for the positive uniaxial crystal ; ( 3 ) when the crystal optical - axis parallel to the waveguide plane, for the positive uniaxial crystal material, the principal mode of the waveguide is a te wave, which can be excited by the light at any frequency ; when the light frequency satisfies a single mode propagation condition, there will be only the principal mode propagating in the waveguide, otherwise some of the higher order modes can be excited, which are neither te modes, nor tm modes, but the hybrid guided modes
本文就是在此背景下，利用金屬波導和單軸晶體的一些特性，結合麥克斯韋方程組和波導的邊界條件，從三種不同的情況研究了光在對稱平面單軸晶體金屬波導（波導層是單軸晶體，兩個波導界面均為金屬）內的傳輸特性，其主要貢獻為，首次解析地得到了這種波導結構下模式場的精確解，並發現了一些有用的特性： （ 1 ）模式場的性質因單軸晶體的性質不同而異； （ 2 ）當單軸晶體光軸位於波導界面法方向與傳輸方向構成的平面內時，波導中傳輸te波和tm波，只不過其主模因單軸晶體的性質不同而異，當波導層介質為負單軸晶體時，波導主模是te波主模，而波導層介質為正單軸晶體時波導主模是tm波主模。 （ 3 ）當單軸晶體光軸位於波導面內時，對于正單軸晶體，波導的主模是橫電波te _ 0模，任何頻率的光波均可激勵該模式；當光波波長滿足一定條件時，波導內傳輸單模，否則，將激勵起高階模式，高階模即匪te波，也匪tm波，而是兩者耦合而成的混合模。 -
The key parts of barretter are made of irf840 field - effect transistor, the magnetic ring and high frequency choking coil which adopting negative temperature index. such components can provide barretters a wide applicable voltage 160v - 250v. low power consumption, minor temperature rise, stable functions, long life - span
鎮流器核心元件採用irf840場效應三極體，磁環及高頻扼流圈採用負溫系數，這樣的元件選擇使整流器適用電壓范圍寬160v - 250v ，功耗低，溫升小，性能十分穩定，確保其擁有很長的壽命。 -
Ac alternating current ( ac ) is electric current that alternates between a positive maximum value and a negative maximum value at a characteristic frequency, usually 50 or 60 cycles per second ( hertz )
交流交流是指電流在正負最大值之間以特定的頻率變動，通常頻率為50或60赫茲。 -
The essence of edid is to set up a normal behavior fuzzy sub collection a on the basis of watching the normal system transfer of the privilege process, and set up a fuzzy sub collection b with real time transfer array, then detect with the principle of minimum distance in fuzzy discern method the innovation point of this paper is : put forward the method of edid, can not only reduce efficiently false positive rate and false negative rate, also make real time intrusion detection to become possibility ; have independent and complete character database, according to the classification of monitoring program, design normal behavior and anomaly behavior etc., have raised the strongness of ids ; use tree type structure to preservation the character database, have saved greatly stock space ; in detection invade, carry out frequency prior principle, prior analysis and handling the behavior feature of high frequency in information table, have raised efficiency and the speed of detection, make real time intrusion detection to become possibility ; have at the same time realized anomaly intrusion detection and misuse intrusion detection, have remedied deficiency of unitary detection method
這種方法的實質是在監控特權進程的正常系統調用基礎上建立正常行為模糊子集a ，用檢測到的實時調用序列建立模糊子集b ，然後用模糊識別方法中的最小距離原則進行檢測。本文的創新點是：通過對特權進程的系統調用及參數序列的研究，提出了基於euclidean距離的入侵檢測方法edid ，不僅能有效降低漏報率和誤報率，而且使實時入侵檢測成為可能；設計有獨立而完整的特徵數據庫，根據被監控程序的類別，分別設計正常行為、異常行為等，提高了檢測系統的強健性和可伸縮性；特徵數據庫按樹型結構存儲，大大節省了存儲空間；在檢測入侵時，實行頻度優先原則，優先分析和處理信息表中的高頻度行為特徵，提高檢測的速度和效率，使實時入侵檢測成為可能；同時實現了異常入侵檢測和誤用入侵檢測，彌補了單一檢測方法的不足。 -
The positive and negative frequency expressions of quasi - monochromatic optical fields of a pulse in fiber - optic communication and the positive and negative frequency forms of fourier transformations and nonlinear schr ? dinger ( nls ) equations are discussed
摘要討論光通信中脈沖的準單色光光場的正負頻表示，正負頻形式的傅里葉變換，正負頻形式的非線性薛定諤方程及它們之間的關系。 -
The dissertation discussed the theories of second - harmonic generation for negative uniaxial optical crystal and summarized properties of nonlinear optical crystals, which are subjected to ultraviolet second - harmonic generation, and represented the theorizational law of double frequency crystal select ( tldfcs ). at present, bbo crystal is the most subjected to commercial crystal of ultraviolet second - harmonic generation according to compared kdp, bbo, clbo, kabo and kbbf crystals based on tldfcs
論述了負單軸晶體的倍頻理論，總結了適用於紫外倍頻的非線性光學晶體的特性，提出了倍頻晶體選擇的理論依據，並根據該依據通過比較，最後選定bbo晶體為目前最適宜用於產業化的紫外倍頻晶體。 -
Fuzhon jingmei biotechnology dvelopany limited since its establishent has become the main instrument of the high potential for r & d, production, marketing, iresearch and developent of high - potential therapeneutic apparatus for one set ; including electrostatic field, the negative electric field, the low - frequency field, high frequency anions, such as far - infrared
福州靜美生物技術開發有限公司自成立以來主要自立於高電位健康器的研發、生產及銷售，我公司研發的高電位健康器集多種功能為一體；包括有靜電場、負電場、低頻場、高周波、負離子、遠紅外等。 -
( 5 ) the frequency modulation effects of positive ( negative ) dipole and positive ( negative ) unipole forcing source on lfo have the same sensitive region
（ 5 ）正（負）偶極和正（負）單極對大氣的低頻振蕩調制有相同的敏感區。 -
As a result, an amplifier of this type may have outstanding low frequency power supply rejection, but the negative supply rejection is fundamentally limited at high frequencies
因此，此類放大器會有傑出的低頻供電抑制，但負電壓供電會被限制在高頻 -
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。 -
Many experiments on the effects with the change of several parameters, such as initial charging current, amplitude and frequency of positive pulses, variety of the amplitude of positive pulses among each charging stages, amplitude and duration of negative pulses, duration between positive and negative pulses, have been performed. the results of analysis and comparison of experimental data verify the validity and feasibility of the fast - charging method. on this basis, a new type of control strategy is advanced
就充電過程中的起始充電電流、正脈沖的幅值、正脈沖的頻率、各充電級之間正脈沖幅值的變化幅度、負脈沖的幅值、負脈沖的持續時間、正負脈沖之間的停歇時間等幾個參數進行了大量的實驗，對實驗數據進行分析和比較，驗證了快速充電方法的有效性和可行性，在此基礎上提出了一種新型快速充電控制策略。 -
According to these theories we know the reason of the emergence of low frequency oscillation is lacking positive damping even appearing negative damping. this problem can be classified as dynamic stability
從而得出，電力系統低頻振蕩是由於系統正阻尼不足甚至產生負阻尼而引起的，可以將其歸類為動態穩定問題。 -
Through the deep study of f. d. demello dynamic model of electromechanical transition and synchronous generator theory, we proposed a new control strategy of excitation device that can eliminate the negative - damping phenomenon, which is directly against the cause of producing negative - damping represented as low frequency oscillation in the system
通過深入研究f . d . demello機電暫態的動力學模型以及同步發電機理論，針對系統產生負阻尼即低頻振蕩的原因，我們提出了一種新的可消除負阻尼現象的勵磁控制策略。 -
2. we studied the relationship between the locking bandwidth and the injected signal light intensity and verified that the locking bandwidth is asymmetric. the negative frequency detuning is larger than positive frequency detuning
實驗證實了鎖頻范圍是不對稱的，負失諧范圍大於正失諧范圍，並且注入功率越大，鎖定范圍越大。 -
The variable polarity power supply circuit uses two stages full - bridge inverter, the former inverter is regarded as a constant - current source with fast dynamic response, and supplys energy for the second one, and the latter one is to produce variable polarity current excellently, and low - frequency pulse current by variable polarity power supply is used to reduce input energy and control the shape of weld bead while welding. a series of high - frequency pulse current is superposed on direct - current - electrode - negative ( dcen ) current through the high - frequency pulse power supply, which is used to compress the arc and improve process of crystallization
其中變極性電源採用二次全橋逆變結構，一次逆變提供快速的響應速率並給二次逆變提供能量，二次逆變提供良好的變極性性能，使輸出能量最優化，並用其低頻電流特性減小電弧線能量，控制焊縫成形;高頻脈沖電源提供的高頻電流疊加在反極性電流dcen上，利用電流的高頻特性壓縮電弧，改善焊縫金屬結晶過程。
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