critical frequency 中文意思是什麼

This paper mainly discusses the designing and testing method to the dds acousto - optic mode locking. it also makes some further analysis on the critical technology - - - - - - the transducer acoustical membrane matching and transducer thinning, which can directly affect the performance of acousto - optic elements. it then analyses the heat effect of acousto - optic elements and the technology of transducer thinning by developing ion - beam sputtering of high frequency acousto - optic elements

本文重點討論了dds聲光鎖模器的設計及測試方法，討論和分析了影響聲光器件性能的關鍵工藝換能器聲學膜層匹配和換能器減薄工藝，對聲光器件的熱效應進行了測試分析，對離子刻蝕法聲光換能器減薄新工藝作了一定的探討。

Around 40 ; the neutral curve obtained by the growth rates of the temperature fluctuation has a ringlike curve separated from the main branch of nachtsheim s calculation by velocity fluctuation at the lower grashof number side ; and its phase velocity is close to the maximum mean velocity where the critical layer of the eigenmode locates. the thermal fluctuation decays rapidly as the nondimensional frequency above 0. 4, so that it means that the coupling effect between instability wave generated by buoyancy fluctuation and velocity waves by invicid instability seems weak enough for their critical layers in the range of the nondimensional frequency

詳細研究了自然對流邊界層中最早失穩的浮力振型的功率譜波長波速與臨界層位置等基本特徵和它為主導其他振型尚未失穩時按線性理論得到的3種相互獨立振型的振幅分佈。系統地測量了它所對應的溫度和速度漲落的振幅增長規律和中性曲線，實驗結果表明，溫度漲落的中性曲線在低格拉斯霍夫grashof數

The stability output second harmonic generation ( shg ) experiment results of single - longitudinal mode and multi - longitudinal mode with long cavity were explained reasonably with these rate equations. the high polarization of fundamental wave in the isotropic laser media nd : yag with type - i critical phase - matching lbo was studied with the rate equations including polarization of fundamental light. using the polarization function of lbo, a quartz full - wave plate was introduced into the cavity, a kind of birefringent filter by considering the combination of the polarization function of the type - i critical phase - matching doubling frequency crystal lbo and the quartz whole - wave plate was constructed

將腔內多縱模倍頻速率方程推廣應用到準三能級藍光激光器中，分析了一個縱模、兩個縱模、多個縱模時的噪聲情況，合理地解釋了實驗中激光器單縱模運轉以及長腔多縱模運轉時穩定輸出的實驗現象，同時利用該速率方程分析了以各向同性激光晶體nd : yag為工作物質，類臨界相位匹配lbo為倍頻晶體的藍光激光器中基頻光偏振特性，合理利用類臨界相位匹配lbo倍頻晶體的偏振特性與引入的石英晶體全波片構成雙折射濾光片，通過選單頻來抑制噪聲，獲得了藍光低噪聲的穩定輸出。

Chapter 2 sets forth the structure of if ( intermediate frequency ) digital software radio, the critical theory of software radio and the signal processing technique about it

第二章介紹了中頻數字化軟體無線電的結構，並闡述了軟體無線電的關鍵理論和軟體無線電中的信號處理技術。

In this paper, the research progress of ac losses of high temperature superconductors and the existing problems on ac losses investigation are introduced ; the characteristics of the critical current and ac losses of hts tapes, stacked tapes and hts coil, such as electro - magnetic characteristics, the anisotropy, the mechanics characteristics and the effects of insular layer between stacked tapes and the influence of frequency of ac transport current etc, are investigated

本文在系統介紹高溫超導體的交流損耗及其研究現狀與存在問題的基礎上，從理論和實驗兩方面，研究了bi系高溫超導單根帶材、多根超導並聯組合帶材、及超導線圈的臨界電流與交流損耗的特性：重點研究了交流損耗與臨界電流的電磁特性、機械特性、各向異性特性、及帶間絕緣層與傳輸電流頻率對交流損耗的影響等。

The reflected light spectrum from interaction of uv laser with solid plasma was measured to investigate the frequency shift due to doppler effect of expanding critical density

測量了紫外超短脈沖激光等離子體中的光譜頻移，分析表明是有質動力和等離子體熱壓力共同作用的結果。

The future wireless mobile communication systems are expected to provide ubiquitous, high - quality, and high - rate mobile multimedia transmission. however, hostile multipath fading radio conditions give rise to serious inter - symbol interference ( isi ) ; even worse, wireless channel are often time varying, which makes the system more vulnerable and more difficult to track the channel state. orthogonal frequency dvision multiplexing ( ofdm ), which is inherently resistant against isi, has invoked a popular research interest in recent years, and has been a promising candidate technology of the physical layer for future weideband high - date - rate wireless communications. notwithstanding, ofdm is much more vulnerable to errors of both time and frequency synchronization and to that of channel estimation, and how to obtain correct timing and channel estimation efficiently is highly critical to ofdm systems. the dissertation will focus on both of the aspects of ofdm systems mentioned above

但是無線環境的多徑特性造成通信系統中嚴重的符號間干擾，同時無線通道的時變性使得通道特性跟蹤復雜。而正交頻分復用技術（ orthogonalfrequencydivisionmultiplexing ， ofdm ）正是一種解決符號間干擾的有效傳輸手段，因此ofdm技術作為未來寬帶高速率無線通信的物理層候選技術在當前引起了一股研究熱潮。但ofdm系統對定時同步誤差和通道估計誤差非常敏感，如何在ofdm系統中準確快速地實現符號同步和通道估計是至關重要的，本論文將重點針對這兩個問題進行討論。

This article describes a way of special ultrasonic system which monitors thermal stress in seamless welded rails. this monitoring system is a non destructive testing system, which adopts avr mcu and high - precise time chip processing as the core of it, and adopts the critically refracted longitudinal wave as the object of measuring. my studying focuses on the theory of the monitoring system, which will be listed in this arctile : according to the snell theory, the theory of motivating of critically refracted longitudinal wave is described in details, and the finite element software is used to emulate the propagating course. the formulas of calculating the pts of swr are taken from the acoustoelasticity theory, and the calculating the parameters is introduced. according to assemble materials, three kinds of ways of monitoring the pts of swr using critically refracted longitudinal wave are described, which are measuring the sound - time in changeless distance, ultrasonic critical - angle refractomery and frequency spectrum, the first way of ways is used in this experiment system. the factors, which effect the monitoring system, are assaid in some degree based

本文的研究工作重點在無縫焊接鋼軌溫度應力測量系統的理論模塊，包括根據snell原理，研究極限折射縱波的激發機理，並使用有限元軟體ansys進行模擬;根據聲彈性理論以及公式推導出計算無縫焊接鋼軌中的溫度應力的公式，並對其中參數的求解方法進行介紹;根據收集的資料，介紹了三種使用極限折射縱波測量無縫焊接鋼軌溫度應力的方法，即固定距離測量聲時法、臨界角折射法和頻譜分析法，本實驗系統使用的是第一種;根據實驗經驗以及相關資料，分析了影響極限折射縱波測量溫度應力的幾個因素，並提出了相應的解決方法;根據實驗系統的需要，獨立設計並加工出相關配套的實驗設備，包括實驗鋼塊、有機玻璃楔塊、固定件、載荷外框裝置等。

The electric field, magnetic field, critical frequency, surface current, power transmission and attenuation, as well as te and tm modes in waveguides are discussed

給出計算等效矩形截面波導的te模和tm模、電磁場、臨界頻率、波導壁電流、功率傳輸和衰減的公式。

The dynamic character of the rotor system is the same as that without magnetic field when the magnetic field frequency is over a critical frequency, and the sinusoidal magnetic field cannot control the dynamic performance of the disk type mr fluid damper

當磁場的頻率高於一個臨界頻率后，轉子系統的動力特性與無磁場時的動力特性相同，正弦磁場不能夠控制磁流變流體阻尼器的動力特性。

Numerical simulations were done to show the distortion of the wavefront and the interference pattern under several kinds of typical plasma density distributions. the ray path in plasma was calculated by the numerical solution of the vector equation of light ray, when the plasma density was closing to the critical electron density of the laser frequency. through the simulations, the factors that influence the measurement were found out under different density distributions and shapes of plasma

在此基礎上，採用數值模擬的方法，計算了在幾種典型的等離子體密度分佈下，激光波面的變化和產生的干涉圖樣；並用光線矢量微分方程的數值解法計算了當等離子體密度接近光頻臨界電子密度時，光線在等離子體中的傳播路徑，從中掌握了在不同的等離子體密度和形狀下，進行干涉測量所應估計到的因素。

Difference of critical twinkle visual frequency of different chromatic light between normal persons and patients with different type of schizophrenia

正常人與不同類型精神分裂癥患者不同色光臨界閃爍視頻率的差異

This text completely and systematically studies the status and the development of the pyrolysis and the fluidization of biomass, which distill the bio - oil in the domestic and international area, as well as the existing problems. this thesis primarily include following aspects : ( l ), by experimenting and measuring the energy ( heat value ) and the content of c, h, n chemical element of right 20 kinds of common biomass, on the base of the experimental result, and respectively established the biomass energy predict experiment formula with the element of h and c is from change, and passed the ro. os examination, which provides the basis and convenience for flash pyrolysis fluidization device energy to convert the rate to compute with biomass energy utilization calculation ; ( 2 ), proceeded the tg and dtg experimentation equal velocity ( 10 ? / min, 20 ? / min, 40 ? / min, 60 ? / min ) heating and constant temperature heating by studying on eight kinds of biomass samples, according to the experimental data and arrhenius formula, we established the dynamics model of pyrolysis of, then, using the goast - redfern and p function, we also solved the dynamics parameters and analyze out every kind of biomass ' s frequency factor and parameters of activation energy, and established the every kind of dynamics model of pyrolysis of biomass, all of these provide the theories and basis to make sure the reactor ' s flash pyrolysis work temperature scope design and the describing of pyrolysis reactor dynamics ; ( 3 ), in order to study and ascertain the process of heat completely getting to pyrolysis time of varied size biomass particles, we observed and measured the ratio of length and diameter ( l / d ) with the varied biomass through electron microscope, we concluded the l / d ratios usually is from 5. 0 to 6. 0, the average is 5. 3 ; ( 4 ), we studied the process of biomass transiting and the theory of complete pyrolysis time with the theory of complicated heat field, we got the time ( t ) of the varied size biomass particles arriving to complete pyrolysis, and we knew that the complete pyrolysis time and the time which get to the biggest production ratio are identical, all of these studies provide the theory base for design and forecasting the flash pyrolysis reactor solid state resort time ; ( 5 ), according to the above experiment result, synthesize to make use of the engineering the mechanics, engineering the material, machine the design to learn the principle, deduce, establish the theory of rotation cone flash pyrolysis reactor material resort time ( t ) and reasonable rotation velocity ( or frequency ) relation theory ; and ( 6 ), we gave the reactor ' s smallest cone angle certain, reactor cone wall strength design theory, the reactor production ability theory, the power design method and the critical rotation velocity theory

本文較全面、系統地綜述了國內外生物質熱解液化制取生物燃油技術研究發展現狀及存在的問題，主要研究內容有： （ 1 ）實驗、測定了20種常見生物質的能量（發熱量）和c 、 h 、 n元素含量，根據實驗結果分別建立了以h和c為自變量的生物質能量預測經驗公式，並通過r _ （ 0 . 05 ）檢驗；為閃速熱解液化裝置能量轉化率計算和生物質能量利用率計算提供了依據和方便； （ 2 ）選擇了8種生物質試樣作了等加熱速率（ 10 min 、 20 min 、 40 min 、 60 min ）和恆溫加熱的tg和dtg實驗，根據實驗數據和阿倫尼烏斯公式建立了生物質熱解反應動力學微分方程，並採用goast - redfem積分法和p函數對其動力學參數進行了求解，解析出各種生物質的頻率因子和活化能參數，進而建立了各種生物質的熱解動力學模型，為科學確定反應器的閃速熱解工作溫度范圍及熱解反應動力學描述，提供了理論和依據； （ 3 ）為研究和確定不同尺度的生物質顆粒中心達到全熱解的時間，在體視顯微鏡下對不同粒度的生物質顆粒的長徑比進行了實驗觀察和測定，得出生物質的長徑比（ l d ）一般在5 . 0 6 . 0之間，平均為5 . 3的結果； （ 4 ）採用復雜溫度場傳熱學理論對生物質傳熱過程及充分熱解時間理論進行了研究，解析推導出了不同尺寸生物質顆粒中心溫度達到充分熱解溫度的時間（ t ） ，得出了理論推導的充分熱解時間與最大產油率的熱解時間相一致的結果，為閃速熱解反應器固相滯留時間設計和預測提供了理論依據； （ 5 ）根據上述實驗結果，綜合運用工程力學、工程材料、機械設計學原理，推導、建立了轉錐式閃速熱解反應器物料滯留時間（ ）與轉速（或頻率）合理匹配理論； （ 6 ）提出了轉錐式閃速熱解反應器的最小錐角設計、錐壁強度設計、生產能力設計理論和功率計算方法及臨界轉速理論等。

Using paper copies of texts and relying on manual counting, they have compiled frequency statistics of a number of grammatical constructions in several colloquial chinese buddhist texts written from the period of the three kingdoms to the sui dynasty to shed light on the historical evolution of several grammatical patterns in modern chinese. in their second paper, manual counts of representative linguistic elements have revealed critical stylistic differences between the first 32 chapters and the last 23 chapters of the early qing dynasty chinese novel ru lin wai shi

第一篇文章統計了著於三國至隋朝時期的白話佛教書籍的一些文法結構，並闡述了幾種文法模式在現代漢語中的演變過程；第二篇文章統計了清朝的《儒林外史》中具代表性的語言形式，揭示了該書前三十二章與后二十三章之間體裁上的重大差異。

In this paper periodically perturbed hopf bifurcation to lienard equation with limited time delay is sdudied in detail. that is, the influence of small periodic perturbations on system exhibiting hopf bifurcation is sdudied. in particular, the excitation frequency and the critical natural frequency of hopf bifurcation in the cases of harmonic resonance. subharmonic resonance, ultraharmonic resonance, and ultrasubharmonic resonance is discussed. it is shown that in some parameter regions the sestyms exhibit harmonic solution bifurcation, subharmonic solution bifurcation, ultraharmonic solution bifurcation, ultrasubharmonic solution bifurcation and quasi - periodic solution

本文詳細研究了具有限時滯li nard方程的周期擾動hopf分支，即在該系統經歷hopf分支時，研究小周期擾動對系統的影響，特別是討論了擾動頻率與hopf分支周期解的固有頻率在共振、次調和共振、超調和共振、超次調和共振的情形。

As a design method, frequency tuning approach ( fta ) was suggested to be used first to avoid critical frequency ranges

建議人行橋梁設計時應首先採用頻率調整法，使結構自振頻率盡量不落在敏感頻率范圍內。

Flashing frequency, critical flicker frequency

臨界閃變頻率

Thirdly, considering when acoustic wave with a certain frequency or angle is incident upon plates, it will greatly cause the radiation power " translating. this paper details the causes of coincident effect and gets the calculating formula. the conclusion is resulted that thick plate and uniaxial anisotropies can lower critical frequency

針對聲波入射板面時在某一特定頻率或特定入射角度時會使聲輻射能力大大增加並產生聲能的大量透射這一現象，詳細討論了產生吻合效應的條件；並針對工程實際中所應用到的各種尺寸、材質的板分別推導了其吻合頻率和臨界頻率的計算公式，得出了厚板和材料的各向異性均會使結構的臨界頻率下降的結論。

The critical frequency of the sinusoidal magnetic field increases with increasing magnetic field density

磁場強度越大，正弦磁場的臨界頻率越高。

Damping was then determined via exciting the equation at the critical frequency to get the transit decay which was then analyzed with the moving - block method. in chapter 4, the nonlinear dynamic equation of rotor - body system with inter - blade dampers ( taking all possible attachment offsets into consideration, spanwise offset, vertical offset and in - plane offset ) was modeled

本文重點推導了帶葉間減擺器（減擺器帶三個外伸量:展向，垂向和旋轉方向）的旋翼/機體耦合系統的非線性動力學方程，針對該方程提出了一種改進的多槳葉坐標變換方法。