Noise Propagation from Scatter Correction in SPECT MAP Reconstruction
基于图像噪声检测的Harris角点提取方法
＊ ２０１０—０４—１５收到，２０１０－０６．０７改回 ＊瞢 钱成越，男，１９８９年生，本科生，研究方向：图像处理．
万方数据
基于图像噪声检测的Ｈａｒｒｉｓ角点提取方法
ＤｅｔＭ＝２．１Ａ２，ＴｒａｃｅＭ＝２１＋如，Ａｌ、屯为Ｍ的特征值，尺 度因子Ｋ为经验值，通常取０．０４。 １．２算法设计
此，先定义四个方向算子［５］，如图１所示。
ＯＯ
ＯＯ
ＯＯ
引雕 ｌ ｌ
ＯＯ
ＯＯ ＯＯ
ＯＯ
ＯＯ
ｌＯ
。叫。ｏ ０ ｌ
引｝；｜ Ｏ １
ＯＯ ０Ｏ
ｌＯ
ＯＯ
ｏ叫ｏ Ｏ ０
ｌＯ
ｏ
Ｏ０
记四个方向算子的卷积核为Ｋ，对图像上各像素
Ｉ（ｘ，ｙ）进行卷积运算：
ＮｏｉｓｅＶａｌｕｅ＝ｍｉｎ｛ＫＱＩ（ｘ，ｙ）｝
定义如上模板并进行相应卷积运算的依据在于，
５ ８２４ｍｓ
改进后的 Ｈａｒｒｉｓ算子
３ ６３５ｍｓ
运算时间提高 ３７．５９％
第２次
５ ５３２ｍｓ
３ ５５７ｍｓ
３５．７０％
第３次
５ ７２１ｍｓ
３ ６０４ｍｓ
３７．ＯＯ％
第４次
５ ６８３ｍｓ
３ ６０３ｍｓ
３６．６０％
第５次 平均值
５ ８３４ｍｓ ５ ７１８．８ｍｓ
３ ９３１ｍｓ ３ ６６６ｍｓ
３２．６２％ ３５。９０％
３算法的改进
３．１选择梯度算子 通过大量实验，对采用常见的梯度算子进行角点
提取时，处理的优缺点进行总结，如表１所示。
裹１不同梯度算子角点提取优劣对照表
diffusion降噪公式
diffusion降噪公式摘要：1.降噪公式的概述2.降噪公式的原理3.降噪公式的应用4.降噪公式的优缺点正文：1.降噪公式的概述降噪公式，又称为扩散降噪公式，是一种广泛应用于图像去噪领域的数学模型。
其主要目的是通过模糊、扩散等方式降低图像中的噪声，从而提高图像的质量和视觉效果。
2.降噪公式的原理降噪公式的原理主要基于扩散过程。
扩散过程是指在图像中，像素值会沿着一定的方向和距离进行传播，使得图像中的边缘和细节变得模糊。
通过这种方式，可以降低图像中的高频噪声，从而使图像变得更加平滑。
降噪公式主要包括以下几个步骤：（1）选择扩散方向和距离：首先需要选择一个扩散方向和距离，这决定了像素值传播的方向和范围。
通常情况下，会选择与图像的梯度方向垂直的方向作为扩散方向，以保证在扩散过程中不会改变图像的主要结构。
（2）计算扩散矩阵：根据所选的扩散方向和距离，计算扩散矩阵。
扩散矩阵是一个二维矩阵，用于描述像素值在扩散过程中的变化。
（3）应用扩散矩阵：将原始图像与扩散矩阵相乘，得到降噪后的图像。
3.降噪公式的应用降噪公式广泛应用于图像去噪领域，尤其是对于一些低质量的图像，如在高斯噪声、椒盐噪声等噪声影响下的图像。
通过使用降噪公式，可以有效地降低图像中的噪声，提高图像的质量和视觉效果。
4.降噪公式的优缺点降噪公式的优点在于能够有效地降低图像中的噪声，同时保持图像的主要结构不变。
此外，降噪公式具有较好的通用性，适用于多种类型的噪声。
然而，降噪公式也存在一些缺点。
首先，降噪公式会导致图像中的边缘和细节变得模糊，从而降低图像的清晰度。
其次，降噪公式需要选择合适的扩散方向和距离，这需要根据具体的图像特征进行调整，具有一定的主观性。
光能积分透过率 英语
光能积分透过率英语Integral Transmittance of Light Energy.The concept of integral transmittance, also known as overall transmittance, is a crucial metric in optics, particularly when dealing with the propagation of light through various media. It quantifies the fraction of incident light that passes through a material or system, rather than being absorbed, reflected, or scattered. Understanding and optimizing integral transmittance is essential in fields ranging from solar energy conversion to medical imaging.Definition and Importance.Integral transmittance, denoted as T, is defined as the ratio of transmitted radiant power to incident radiant power. It is expressed as a decimal or percentage. A transmittance value of 1 or 100% indicates that allincident light is transmitted through the material, while avalue of 0 or 0% indicates that no light is transmitted.The importance of integral transmittance lies in its ability to provide insights into the optical properties ofa material. It is a key parameter in evaluating materialsfor applications such as optical filters, windows, lenses, and solar cells. By understanding the transmittance properties of a material, engineers and scientists can optimize its performance in these applications.Factors Influencing Integral Transmittance.Integral transmittance is influenced by several factors, including:1. Material Properties: The type of material and its optical properties, such as refractive index, absorption coefficient, and scattering coefficient, significantlyaffect transmittance. Materials with higher refractive indices or stronger absorption tend to have lower transmittances.2. Thickness: The thickness of the material through which light is transmitted plays a crucial role. Thicker materials tend to absorb more light, reducing transmittance.3. Wavelength: The wavelength of the incident lightalso matters. Materials may have different absorption spectra depending on the wavelength, affecting transmittance.4. Surface Finish: The smoothness and cleanliness ofthe material's surfaces can impact transmittance, as roughness or contamination can scatter light.5. Temperature: Changes in temperature can affect the optical properties of a material, thus influencing transmittance.Measurement and Characterization.Measuring integral transmittance typically involves using a spectrophotometer or a similar instrument. These devices measure the intensity of incident and transmittedlight and calculate the transmittance based on these measurements. By varying the wavelength of the incident light, it is possible to obtain a transmittance spectrum, which provides insights into the material's optical properties across different wavelengths.Applications.Integral transmittance has a wide range of applications across various industries:1. Solar Energy: Solar cells rely on high integral transmittance materials to allow maximum sunlight to reach the photovoltaic active layer, thereby enhancing conversion efficiency.2. Optical Communications: In fiber-optic cables, integral transmittance is crucial for minimizing signal loss and ensuring reliable data transmission.3. Imaging: High transmittance materials are essential in medical imaging techniques such as X-ray and MRI, asthey allow better penetration of radiation and improve image quality.4. Photography and Filmmaking: Photographic films and camera lenses require specific transmittance properties to capture and project images faithfully.5. Display Technology: LCDs, OLEDs, and other display technologies rely on transparent materials with high integral transmittance to produce bright and vivid images.Conclusion.Integral transmittance is a fundamental concept in optics that plays a pivotal role in various applications. Understanding and controlling transmittance properties is crucial for optimizing the performance of optical systems and materials. As technology continues to evolve, so will the need for materials with superior transmittance characteristics, driving further research and development in this field.。
2158 IEEE TRANSACTIONS ON ANTENNAS AND PROP
[11] F. D’Agostino, F. Ferrara, C. Gennarelli, R. Guerriero, and G. Riccio, “An effective technique for reducing the truncation error in the nearfield-far-field trnasformation with plane-polar scanning,” Progr. Electromagn. Res., vol. 73, pp. 213–238, 1996.
[3] M. G. Cote an of bistatic electromagnetic scattering measurements by spherical near-field scanning,” in Proc. AMTA Symp., 1993, p. 191.
[13] F. Ferrara, C. Gennarelli, R. Guerriero, G. Riccio, and C. Savarese, “Extrapolation of the outside near-field data in the cylindrical scanning,” Electromagnetics, vol. 28, pp. 333–345, 2008.
影响PETCT图像质量和诊断的诸因素分析
探讨影响PET/CT图像质量及诊断的多种 因素的目的
了解影响PET/CT图像的各种因素
如何获得高质量的PET/CT图像
如何综合PET和CT的图像信息，提高诊 断准确性，尽量减少错误诊断
商品化的PET/CT扫描仪
GE公司
Discovery LS Discovery ST
西门子公司
Biograph HR 、 Biograph HS、 Biograph32 、 Biograph 64
PMT gain图
南方PET中心
Normalization Calibration 1）探测器归一化校准 ，用以校正发射显像资料
探头归一化也称为探测器灵敏度校正。 对PET数据进行图像重建时，基本假设是符合投影线灵敏度一致。 探测器参数的差异，符合投影线与探测器表面夹角不同，都会造 成灵敏度的差异。 对这些造成探测灵敏度差异的因素，进行校正的过程称为探测器 归一化。 对每一条符合投影线来说，都应有一个归一化因子
Six Detector Blocks（nodule)
Detector Cassette
One Block
18环探测器的组成
18 Rings 672 Crystals/Ring
南方PET中心
校准（Calibration）
Blank Scan: 5min, daily Singles /update gain adjustment: 1hr,weekly Coincidence Timing Calibration: 5min,
飞利浦
GEMINI
世界上著名的医疗仪器大公司的参与开发，使 PET/CT的发展突飞猛进
PET/CT组成
PET/CT扫描仪
功能 影像 与形 态影 像的 优化 组合
1米平均声压级 英语
1米平均声压级英语Title: Understanding the Average Sound Pressure Level at 1 Meter.Sound pressure level (SPL) is a measure of the amplitude of sound waves, typically expressed in decibels (dB). It is a crucial parameter in acoustics, describing the intensity of sound perceived by the human ear. When discussing SPL at a specific distance, such as 1 meter, it becomes important to consider the factors that affect sound propagation and attenuation.At a distance of 1 meter from a sound source, the average SPL depends on several variables, including the source's intensity, frequency content, and the environmental conditions. Sound sources with higher intensities, such as loudspeakers or industrial machines, will produce higher SPLs than softer sources like whispers or soft music.Frequency content also plays a role. High-frequency sounds tend to attenuate more quickly than low-frequency sounds due to air absorption. Therefore, if a sound source has a significant amount of high-frequency content, the SPL at 1 meter may be lower than expected. Conversely, if the source emits primarily low-frequency sounds, the SPL may be higher.Environmental conditions can significantly impact SPL. For example, the presence of obstacles, such as walls or furniture, can cause sound waves to reflect, diffract, or scatter, affecting the SPL at the measurement point. Additionally, the temperature, humidity, and air density can influence sound propagation and attenuation.When measuring SPL at 1 meter, it is important to use appropriate instrumentation and techniques. Sound meters, which are specifically designed to measure SPL, are widely available and relatively affordable. These meters typically have a microphone sensor that detects sound waves and converts them into an electrical signal, which is then processed to calculate the SPL.When taking measurements, it is crucial to follow standard procedures to ensure accurate results. This includes positioning the sound meter correctly, avoidingany obstructions that could affect the measurement, and calibrating the meter regularly. Additionally, it is important to consider the frequency response of the meter, as different meters may have different sensitivities to different frequencies.In summary, the average SPL at 1 meter from a sound source depends on the source's intensity, frequency content, and environmental conditions. Accurate measurements require appropriate instrumentation, correct positioning, and adherence to standard procedures. Understanding thesefactors is essential for accurate acoustical measurements and assessments.。
BROADBAND NOISE PREDICTIONS FOR AN AIRFOIL IN A TURBULENT STREAM
For permission to copy or publish, contact the copyright owner named on the first page. For AIAA-held copyright, write to AIAA Permissions Department, 1801 Alexander BellBROADBAND NOISE PREDICTIONSFOR AN AIRFOIL IN A TURBULENT STREAMJ. Casper *and F. Farassat † NASA Langley Research CenterHampton, VirginiaP. F. Mish ‡ and W. J. Devenport §Virginia Polytechnic Institute and State UniversityBlacksburg, Virginia* Research Scientist, Computational Modeling and Simulation Branch, AIAA Senior Member. †Senior Research Scientist, Aeroacoustics Branch, AIAA Associate Fellow. ‡Graduate Student, Aerospace and Ocean Engineering Dept., AIAA Student Member. §Professor, Aerospace and Ocean Engineering Dept., AIAA Senior Member.This material is declared a work of the U.S. Government and is not subject to copyright protection in the United States.AbstractLoading noise is predicted from unsteady surface pressure measurements on a NACA 0015 airfoil immersed in grid-generated turbulence. The time-dependent pressure is obtained from an array of synchronized transducers on the airfoil surface. Far field noise is predicted by using the time-dependent surface pressure as input to Formulation 1A of Farassat, a solution of the Ffowcs Williams – Hawkings equation. Acoustic predictions are performed with and without the effects of airfoil surface curvature. Scaling rules are developed to compare the present far field predictions with acoustic measurements that are available in the literature.Nomenclatureb = airfoil semi-span (m) C= airfoil chord (m)0c= ambient sound speed (m/s) f = frequency (Hz)g = velocity-to-pressure transfer function k = ω/U , convective wave number (rad/m) L = streamwise integral length scale M = Mach number∆P = unsteady surface pressure jump (Pa) p =unsteady surface pressure (Pa)p ′= sound pressure radiated to observer (Pa)r = y x −, radiation vector (m)t = observer time (s)U = freestream speed (m/s)u=streamwise turbulence component (m/s)2u = streamwise mean-square turbulence (m 2/s 2) x= T x x x ],,[321, observer position (m)y= T y y y ],,[321, source position (m) 33Φ= turbulence upwash PSD (m 4/ rad 2-s 2) n φ= random phase variable (rad) λ= f c /0, acoustic wavelength (m) θ = radiation angle from surface in Fig. 2 (m) 0ρ= ambient density (kg/m 3) τ = source time (s)ω= circular frequency (rad/s)ψ= directivity angle in Fig. 13 (rad) =The current work is focused on the correlation of unsteady surface pressure measurements to far field noise. The acoustic analogy [1] provides a framework for this correlation in the time domain. Noise due to unsteady surface loading is mathematically described by the loading source term, or “dipole term,” of the Ffowcs Williams – Hawkings (FW-H) equation [2]. BecauseAIAA 2002-0366the noise due to airflow over a rigid surface is typically dominated by dipole radiation, the acoustic formulations presented in this work are determined by solutions of the FW-H equation with the loading source term, i.e., the thickness and quadrupole terms are neglected.The solution of the FW-H equation can be written in many forms. Acoustic predictions in the present work are performed with the loading noise version of Formulation 1A, of Farassat [3]. In its complete form, Formulation 1A is in current use throughout industry for the design of helicopter rotor blades. The version of Formulation 1A presented herein accounts for loading noise of an airfoil in motion and the effects of surface curvature.In [4], far field predictions similar to those of the current study were reported and shown to compare favorably with experimental measurements of Paterson and Amiet [5]. Formulation 1B [4] was applied to the prediction of far field noise due to incident turbulence on a NACA 0012 airfoil at tunnel speeds ranging from 40 m/s to 165 m/s. Formulation 1B is a recently developed solution of the FW-H equation that was shown in [4] to be equivalent to Formulation 1A. As input to Formulation 1B, the time-dependent airfoil surface pressure was generated by stochastic modeling of the incident turbulence and the airfoil response was approximated with a result from thin airfoil theory [6]. Formulation 1B was then used to predict the far field acoustic pressure as a function in time at a microphone located 2.25 m directly above the geometric center of the upper airfoil surface. The time-dependent acoustic signal was then Fourier analyzed to determine the spectral density of the far field noise.In Fig. 1, the predicted far field spectra for all five tunnel speeds are shown to be in good agreement with the experimental measurements of Paterson and Amiet [5], particularly in the range of 200 Hz to 1500 Hz, where the spectra are peaked. Note, however, that the prediction is most in error, by approximately 5 dB, at the lowest tunnel speed. This error is consistent with the low speed prediction in [5]. This error results from the fact that, as the tunnel speed decreases, the wavelength of the aerodynamic disturbance decreases and eventually become of the order of the airfoil thickness. In this case, the airfoil-turbulence interaction is influenced by the airfoil geometry, in particular by the shape of the leading edge. Therefore, as the free-stream speed decreases, the modeling of the surface pressure with the use of a thin-airfoil transfer function becomes increasingly invalid.One of the goals of the current study is to determine the extent of the error made when thin-airfoil assumptions are incorporated into low-speed incident turbulence noise predictions. In [4], both the input surface pressure and the acoustic formulation were based on the approximation of the airfoil geometry as a flat plate. In the current study, the effects of surface curvature are considered in regard to both input and the acoustic formulation.The particular version of Formulation 1A to be used in this work is described in the following section. The simplified version used herein easily allows the formulation to be used with or without the effects of airfoil surface curvature. Section 3 describes the low-speed wind tunnel experiment of interest and the surface pressure measurements that are used to correlate unsteady loading on a NACA 0015 model to the far field. In Section 4, the flat-plate acoustic formulation is used to predict far field noise using time-dependent pressure on the airfoil surface. This surface pressure is first modeled with thin-airfoil theory and the results are compared with predictions that result from experimentally measured surface pressure. In Section 5, scaling rules are developed that are used to compare the present predictions with acoustic data from [5]. The inclusion of the effects of surface curvature in the acoustic formulation is discussed in Section 6, followed by some concluding remarks.2. Acoustic FormulationFormulation 1A [3] was developed as a method to incorporate acoustic prediction in the design of helicopter rotor blades. Because the tip speeds of rotor blades can approach the speed of sound, Formulation 1A accounts for noise from both loading and thickness sources. However, for the low Mach number flows of interest in the present work, thickness noise can be neglected. A further simplification results from uniform rectilinear flow. The following introduction is required for the presentation of Formulation 1A as it applies to the current problem of interest.Consider a surface moving along a velocity vector V. Let ),,,(321txxxf denote a geometric function that is so defined that 0=f on the surface and 0>f exterior to the surface. The velocity vector and thesurface geometry are related to the coordinate axes as pictured in Fig. 2.Denote by T x x x x ],,[321= the position of an observer, and by T y y y y ],,[321= the position of a source point on the surface (Fig. 2). The unsteady pressure ),(τy p on the surface gives rise to sound that radiates along y x r −= to the observer. Note that the surface pressure is evaluated at source time τ. The sound is described by ),(t x p ′, the perturbation pressure that arrives at the point ),,(321x x x at time t . For the case of uniform rectilinear motion, Formulation 1A can be expressed in the form+ −∂∂=′=dS M r p c t x p f r 020)1(cos /1),(4θτπ (1) dS M r M M p dS M r M p f r r f r n == −−− −−0322022)1()(cos )1()(cos θθ The subscript “ret ” denotes evaluation at retarded time0/c r t −, and θ is the angle subtended by the radiationvector and the surface normal nˆ (Fig. 2.). The term rM M r ˆ⋅= is the Mach number in the radiation direction, where 0/c V M = is the local Mach numbervector of the surface. Also, nM M n ˆ⋅= is the Mach number in the direction of nˆ. Note that, in the case of a flat-plate geometry in the plane 03=x , the surfacenormal nˆ becomes 3ˆe , the vertical coordinate vector, and n M vanishes.3. Experimental Surface Pressure3.1. Experiment Description & InstrumentationMeasurements of unsteady surface pressure were performed with an instrumented NACA 0015 airfoil. The model completely spans the 1.83 m test section of the Virginia Tech Stability Wind Tunnel and has a 0.6096 m chord. This facility test section is 7.32 m long with a 1.83 m-square cross section. At 30 m/s, flow through the empty test section is virtually uniform and of low turbulence intensity (<0.05%). Background noise levels are acceptable for the aerodynamic measurements of interest [7, 8].Measurements for the present study were made at a tunnel speed of 30 m/s (Re = 1.17 x 106) with the model at zero angle of attack (Results at non-zero angles of attack are reported in [9, 10, 11]). A square bi-planargrid is mounted 5.82 m upstream of the airfoil leading edge in the wind tunnel contraction. At the grid location the cross-sectional area is 32% larger than that of the test section. The grid has a mesh size of 30.5 cm, an open area ratio of 69.4%, and generates turbulence with a streamwise integral length scale L = 8.18 cm (13% chord) at 30 m/s. The resulting streamwise turbulence intensity at 30 m/s is 3.93%.The airfoil is instrumented with an array of 96 Sennheiser KE 4-211-2 microphones, embedded in the upper and lower airfoil surfaces over the center 58.5 cm of its span. Fig. 3 shows the array layout on the upper surface of the foil. The layout on the lower surface is a mirror image. Microphones are located in chordwise rows between 1% and 85% of the chord length from the leading edge, and at spanwise separations of between 1% and 96% chord. The spanwise distribution of microphones is designed to take advantage of the homogeneity of the flow in this direction so that the 8 spanwise stations together define some 25 approximately logarithmically spaced spanwise separations. The Sennheiser microphones are calibrated from 4 Hz to 20 kHz with an uncertainty of ±1.5 dB. The effects of the ambient acoustic field were assessed with pressure measurements made with no grid present. These measurements fall several decades in spectral level below measurements with the grid installed. Therefore, pressure data that is taken with the grid installed is considered to be uncontaminated by ambient acoustic field pressure fluctuations. Further details on instrumentation and apparatus can be found in [9, 10, 11].3.2. Instantaneous Pressure FluctuationsThe dominant types of pressure fluctuations arising from the turbulence-airfoil interaction can be clearly revealed through contour plots of the instantaneous pressure. By considering a contour plot of time series in space and time, the propagation speed of various types of pressure fluctuations occurring on the surface of the airfoil are shown. If the spatial axis is normalized on chord length C and the time is normalized as tU /C , a fluctuation which is convecting with the mean free stream velocity will have a 1 to 1 slope on such a contour plot. Similarly, a fluctuation propagating downstream at sound speed will have a slope of U c U /)(0+, approximately 12 to 1, and a fluctuationpropagating upstream at sound speed will have a slope of U c U /)(0−, approximately 10 to 1.Fig. 4 presents such a sample contour plot of the instantaneous surface pressure field on both the pressure and suction sides of the airfoil (positive x -axis indicates pressure side of airfoil). The time series have been adjusted to account for the dynamic response of each microphone and are high pass filtered at 10 Hz to remove low frequency uncertainties that arise from the microphone calibration. Low pass filtering is performed by the data acquisition system (HP1432) to preclude aliasing of the data beyond 500Hz. Fig. 4 shows evidence of eddies striking the leading edge and causing an instantaneous adjustment of angle of attack and consequently, lift (due to the upwash velocity) which is propagated at sound speed (slope of 12:1) across the chord. Additionally, a pressure rise in the leading edge region on one side of the airfoil develops which is balanced by a pressure reduction on the opposing side. After the sound speed adjustment in lift, the eddy begins to convect down the chord close to the mean free stream velocity (1:1 slope). Note that the space-time correlations show that surface pressure fluctuations on the forward part of the airfoil are dominated by disturbances that propagate along the 12:1 slope [10, 11].4. Acoustic Predictions4.1. Problem DescriptionFar field noise is now predicted for the experiment described in Section 3. In order to perform the calculations, a coordinate system is established as in Fig. 5, with the airfoil’s mean-chord plane of symmetry defined by }{}0{21b x b C x ≤≤−×≤≤ in the plane 03=x . The airfoil surface profile is determined by the function )(13x F x =, which is well known for NACA series airfoil profiles, e.g., [12]. For the acoustic predictions in this section, the airfoil geometry will be modeled as a flat plate in the plane 03=x . Therefore, a source location on the surface is of the form T y y y ]0,,[21=, and the surface normal is 3ˆ]1,0,0[ˆe n== at every point. The effects of surface curvature will be discussed in Section 6.An observer is placed at a distance r = 2.25 m directly above the geometric center of the mean-chord plane, i.e. T r C x ],0,2/[=, as in Fig. 5. This observerlocation is chosen to be the same as the primary microphone location in [5]. In Section 5, scaling rules are developed to scale the measurements in [5] to serve as estimates against which the present predictions can be compared.Noise is predicted, using Eq. (1) with surface pressure given by a theoretical formulation and by experimental measurements as described in Section 3. Results from both cases are compared.4.2. Analytic Surface PressureIn [13], Amiet developed a frequency-domain formulation for the prediction of noise due to an airfoil immersed in homogeneous, isotropic turbulence. The source in Amiet’s formulation, i.e., the airfoil response to an unsteady surface pressure, was entirely characterized by the incident velocity field. The velocity field is thereby expressed as a linear superposition of periodic gusts that convect at the freestream speed U over a flat plate of finite chord and infinite span.In [4], a time-domain surface pressure model was developed along the same lines as the frequency-domain source model of Amiet [13]. As in Amiet’s analysis, it was determined that, for an observer in the plane 02=x , only the zero spanwise wave number in the turbulent velocity spectrum contributes to the acoustic signal. This result greatly simplifies the source model and enables the surface pressure ),(τy p in Eq. (1) to be expressed as a function of time t , the streamwise surface coordinate 1y , and the streamwise wave number U k /1ω=. (See [4] for details.) Thus, for acoustic prediction purposes, the unsteady pressure jump ∆P across the airfoil can be approximated bytU k i n i n NNn n n ek y g e A U t y P ,1),(2),(,1101φπρ−=≈∆ (2)N n k n k n ±±±=∆=,,2,1,0,1,1N k k N /,11=∆where 0ρ is the ambient density and ),(11k y g is a transfer function that is derived from thin airfoil theory [6]. Also, N k ,1 is an “upper cutoff” wave number, beyond which the spectral amplitude is considered negligible or is out of range of experimental measurement. The phase angles }{n φ are independent random variables uniformly distributed on ]2,0[π. The gust amplitudes }{n A are given by21])0,([1,133k k A n n ∆Φ= (3)where ),(2133k k Φis the two-component power spectral density (PSD) of the upwash component of the turbulence. An expression for this upwash PSD is obtained in [13] by integrating the von Karman formula [14] over all 3k ; the result is: 3/722212221422133])/()/(1[94),(e e e k k k k k k k u k k +++=Φπ (4a)where 2u is the streamwise mean-square turbulence,and e k is the peak wave number given by LL 747.0)3/1()6/5(≈ΓΓ=πe k (4b) where L is the streamwise integral length scale. Evaluation of the time-dependent surface pressure by Eqs. (2) and (3) is consistent with stochastic modeling theory, e.g., [15]. Eq. (1) will be applied in a real-valued, one-sided form )0(N n ≤≤; details can be found in [4].In order to use the above analytical formulation as input to an acoustic prediction, values for the integral length scale and the mean-square turbulence are taken from the experimental measurements described in Section 3.1. The lower bound on frequency, and therefore the fundamental frequency, is chosen to be 10 Hz; the upper bound is chosen at 2500 Hz, with a numerical bandwidth Hz 10=∆f . The physical duration of the calculation is one period of the fundamental, i.e., s 1.0=T . The time-step is chosen as N T t 2/=∆ so that the numerical solution is sampled at the Nyquist frequency. The surface integration in Eq. (1) is performed on a 100×10 surface grid shown in Fig. 6. The reason for the coarseness of the mesh in the 2y direction is that the analytic surface pressure has no variation in that direction, and for the span length and observer distance of interest, the prediction is relatively insensitive to additional resolution in 1y [4]. Note that the grid is clustered near the leading edge because of the rapid increase in the transfer function ),(11k y g near 0=x (see [4]).4.3. Experimental Surface PressureThe prediction of incident turbulence noise with measured surface pressure will follow the same reasoning as with the analytical formulation in Section 4.2. That is, the spanwise variation of the surface pressure will be ignored with respect to its influence on the acoustic signal.The pressure jump across the mean chord plane will be modeled with measurements from the chordwise array of 13 transducers that are located between 1% and 85% of the chord length (Fig. 3). For integration purposes, the pressure jump will be considered piecewise constant along the chord. To this end, let the set 141,1}{=i i y denote a discretization of the chord withC y y y y i i =<<<<<=+14,11,1,11,10 (5)such that each interval ),(1,1,1+i i y y in Eq. (5) contains a transducer location m y ,1 at or near its center. Then, for acoustic prediction purposes, the surface distribution of the pressure jump is 1,11,1,11,),(),(+≤<∆=∆i i m y y y t y P t y P (6a)on each of the 13 intervals determined by the discretization in Eq. (5). The pressure jump at each transducer location is calculated by the difference between simultaneously measured pressures on the lower and upper surfaces, i.e., ),(),(),(,1,1,1t y pt y pt y P m m m −=∆ (6b)The grid in Fig. 7 shows the 13×10 surface elements that are used to integrate the surface pressure in Eq. (6a). For purposes of the Fourier analysis that is required to calculate the far field spectrum, the measured surface pressure is assumed to be of spectral content that is dictated by its time duration T = 1.28 s and a sampling rate of 1600 Hz. On this basis, the measured data is presumed periodic with a frequency range up to 800 Hz. However, the low pass filtering of the data (Section 3.2) curtails reliability of the data beyond 500 Hz. Furthermore, an extensive analysis of these data indicates that measurements from transducers located downstream of the 20%-chord location contain enough turbulent boundary layer noise to make the contribution from the freestream turbulence difficult, if not impossible to detect. Therefore, the pressure jump in Eq. (6a) is zeroed for all stations downstream of the 20%-chord location, i.e., for 8≥m .4.4 Acoustic ResultsBecause the spanwise variation in the surface pressure is neglected, the amount of physical span that is chosen for the acoustic prediction is arbitrary and is chosen as 2b = 0.53 m, as in the experiment in [5]. Fig. 8 shows the far field spectra for the two input surface pressure jumps, analytical and experimental. The spectrum with experimental input has been averaged over 128 records. It is not surprising that the theoretical prediction is higher than the prediction with experimental input. This result is consistent with the over-prediction of the theory relative to acoustic measurements at the lowest tunnel speed in Fig. 1. Some words on the accuracy of the prediction with measured surface pressure are in order. Unfortunately, far field measurements for the present experiment are not available for comparison. Far field measurements from [5] will be scaled for this purpose in Section 5. There is also the issue of using the data in the form of a pressure jump across a flat plate. This should be a reasonable approximation, providing that the observer is sufficiently far away from the plane of the airfoil mean chord, where the effects of surface curvature cannot be ignored, as will be discussed in Section 6.5. Scaling Rules5.1. Amplitude ScalingFor scaling purposes, it is convenient to consider the relative contributions of the terms in Eq. (1), under the conditions of low Mach number and an observer that is in the acoustic and geometric far fields, i.e.C r r M >>>><<,,1λ(7)where f c /0=λ is a typical acoustic wavelength ofinterest. In this case, θ and M r are small, and the differences in retarded time can be neglected. If, in addition, the surface is in the plane 03=x , then n M vanishes. Under these conditions, the first integral in Eq. (1) clearly dominates the acoustic signal, as it is proportional to 1/r , whereas the second and third integrals are proportional to 1/r 2. Therefore, the acoustic formulation is approximated by dS y p rc t x p f =∂∂≈′00,(1),(4ττπ (8) where r is a mean value of the distance r , and 0/c r t −=τ is the mean retarded time.If the surface pressure jump in Eq. (2) is substitutedfor ),(τy p in Eq. (8), and the surface 0~=f is defined by the planar geometry in Section 4.1, the result is)(,1020,1),(n n U k i n n n NNn ek i I A rc U b t x p φτρ+−=≈′ (9a)where1,110),(dy k y g I n C n =(9b)Now, consider the comparison of noise levels between two experimental states A and B . What distinguishes these “states” is the variability in the airfoil model and the flow field. For the present problem, these variables are b , C , U , 2u , and L . The measure of comparison is the sound pressure level (SPL ), defined by=2ref2log 10)(P P f SPL n n (10)where 2n P is the PSD of the acoustic pressure-squared at the frequency n f , the over-bar denotes a time average, and ref P is a reference pressure most commonly taken to be 20 µPa. The values of the pressure spectrum }{n P are the resulting amplitudes of a Fourier analysis of the time series in Eq. (9a). Suppressing the spatial dependence, Eq. (9a) can be re-written in the form−==′NNn i n n e qt p τωˆ)( (11a) wheren i n n n n e k i I A rc U b q φρ,1020ˆ= (11b)It can be shown (see e.g., [16]) that the time average of 2)]([t p ′can be evaluated as=−===′′=′Nn n NNn n P qt p t p t p 022*2ˆ)]()][([)]([ (12)where the star superscript denotes a complex conjugate. In order to compare noise levels between the two states, let the subscript notation A )(⋅ and B )(⋅represent quantities that are evaluated with respect to states A and B , respectively. Using Eqs. (10) – (12), the desired SPL differential, for N n ≤≤0, is evaluated by[][]==−2222ˆˆlog 10)()(log 10)()(An Bn A n B n A n B n qq P P f SPL f SPL (13)where 222224202*2ˆˆˆnn n o nn n A I k rc U b q q qρ== (14) Note that the surface pressure amplitudes }{n A are presumed real. Using the result of Eq. (14), the SPL differential in Eq. (13) becomes[][]=−A n B n f SPL f SPL )()( (15)222422)()()()(log 10A n B n A n B n A n B n A B A B B A A A I I k k U U b b r rIn [6], it is shown that n I is proportional to n k /1. Using this result and the definition of n A in Eq. (3), the scaling rule in Eq. (15) becomes[][]=−A n B n f SPL f SPL )()( (16)∆∆ΦΦA B A B A B A B B A k k U U b b r r )()(log 103333422where 33Φ is interpreted as )0,(133k Φ, the zero-thspanwise wave-number component of the upwash PSD defined in Eqs. (4a) and (4b).5.2. Frequency ScalingThe effect of 2n I on the magnitude scaling in Eq. (15) has already discussed. Its effect can be at least as significant in regard to the frequency f n . The transfer function ),(,11n k y g in Eq. (9b) contains the factor C k i e , which makes for a linear proportionality between the frequency f n and the chord length C [6]. Therefore, when B A C C ≠, A n f SPL )]([ is not scaled to B n f SPL )]([ at the same frequency f n , as implied by Eq.(16). The proportionality between the two frequencies f A and f B isA BAB fC C f =(17) Note that the scaling rules in Eqs. (16) and (17) do not account for directivity. This is not a concern for the present problem where the observer location has been chosen to match the far field microphone position of Paterson and Amiet [5], whose far field data will be scaled for comparison.5.3. Scaling for Predictions and MeasurementsIn order to test the validity of Eqs. (16) and (17), states A and B are as defined in Table I below.Table I. Experimental States A and B.These two states A and B are, respectively, the 40 m/s test case from Paterson and Amiet [5] in Fig. 1, and the present test case of Mish [9, 10]. Note that the observer distance of 2.25 m and the airfoil span of 0.53 m are the same for both states.Fig. 9 shows theoretical acoustic predictions for states A and B in Table I, using the analytic surface pressure in Eqs. (2) – (4) as input to Eq. (1). The symbols represent a scaling prediction for state B that results from using the theoretical prediction for state A as input to Eqs. (16) and (17). The scaled results show excellent agreement with the State B prediction for frequencies above 100 Hz. The error is one dB or less for frequencies down to 40 Hz. The error is expected to increase for low frequencies because of the condition that relates the observer distance to the acoustic wavelength, given in Eq. (7). For a given problem, the lower frequency bound for acceptable scaling error is a function of the quantities in Eq. (7).It is not surprising that the scaling results in Fig. 9 are so successful, because the scaling rules in Eqs. (16) and (17) are derived from the same theory that is used to predict the spectra in Fig. 9. The more important determination is the extent to which the far field。
通讯词汇翻译
通信 Communication通信 Communication 1A安全地线 safe ground wire安全特性 security feature安装线 hook-up wire按半周进行的多周期控制 multicycle controlled by half-cycle 按键电话机 push-button telephone set按需分配多地址 demand assignment multiple access(DAMA)按要求的电信业务 demand telecommunication service按组编码 encode by groupB八木天线 Yagi antenna白噪声 white Gaussian noise白噪声发生器 white noise generator半波偶极子 halfwave dipole半导体存储器 semiconductor memory半导体集成电路 semiconductor integrated circuit半双工操作 semi-duplex operation半字节 Nib包络负反馈 peak envelop negative feed-back包络延时失真 envelop delay distortion薄膜 thin film薄膜混合集成电路 thin film hybrid integrated circuit保护比（射频） protection ratio (RF)保护时段 guard period保密通信 secure communication报头 header报文分组 packet报文优先等级 message priority报讯 alarm备用工作方式 spare mode背景躁声 background noise倍频 frequency multiplication倍频程 actave倍频程滤波器 octave filter被呼地址修改通知 called address modified notification被呼用户优先 priority for called subscriber本地PLMN local PLMN本地交换机 local exchange本地移动用户身份 local mobile station identity ( LMSI)本地震荡器 local oscillator比功率(功率密度) specific power比特 bit比特并行 bit parallel比特号码 bit number (BN)比特流 bit stream比特率 bit rate比特误码率 bit error rate比特序列独立性 bit sequence independence必要带宽 necessary bandwidth闭环电压增益 closed loop voltage gain闭环控制 closed loop control闭路电压 closed circuit voltage边瓣抑制 side lobe suppression边带 sideband边带非线性串扰 sideband non-linear crosstalk边带线性串扰 sideband linear crosstalk边带抑制度 sideband suppression边角辐射 boundary radiation编号制度 numbering plan编解码器 codec编码 encode编码律 encoding law编码器 encoder编码器输出 encoder output编码器总工作时间 encoder overall operate time编码效率 coding efficiency编码信号 coded signal编码约束长度 encoding constraint length编码增益 coding gain编译程序 compiler鞭状天线 whip antenna变频器 converter变频损耗 converter conversion loss变容二极管 variable capacitance diode变形交替传号反转 modified alternate mark inversion便携电台 portable station便携设备 portable equipment便携式载体设备 portable vehicle equipment标称调整率（标称塞入率） nominal justification rate (nominal stuffing rate) 标称值 nominal value标称呼通概率 nominal calling probability标准码实验信号 standard code test signal (SCTS)标准模拟天线 standard artificial antenna标准频率 standard frequency标准时间信号发射 standard-time-signal emission标准实验调制 standard test modulation标准输出功率 standard power output标准输入信号 standard input signal标准输入信号电平 standard input-signal level标准输入信号频率 standard input-signal frequency标准信躁比 standard signal to noise表面安装 surface mounting表示层 presentation layer并串变换器 parallel-serial converter (serializer)并馈垂直天线 shunt-fed vertical antenna并行传输 parallel transmission并行终端 parallel terminal拨号错误概率 dialing mistake probability拨号后延迟 post-dialing delay拨号交换机 dial exchange船舶移动业务 ship movement service船上通信电台 on-board communication station ,ship communication station船用收音机 ship radio串并变换机 serial to parallel (deserializer)串并行变换 serial-parallel conversion串话 crosstalk垂直方向性图 vertical directivity pattern唇式传声器 lip microphone磁屏蔽 magnetic shielding次级分布线路 secondary distribution link猝发差错 burst error猝发点火控制 burst firing control存储程序控制交换机 stored program controlled switching system转贴于：我翻我译我也来说两句查看全部评论相关评论translatorcz (2007-2-03 13:47:45)D大规模集成电路 large scale integrated circuit (LSI)大信号信躁比 signal-to-noise ratio of strong signal带成功结果的常规操作 normal operation with successful outcome带宽 bandwidth带内导频单边带 pilot tone-in-band single sideband带内谐波 in-band harmonic带内信令 in-band signalling带内躁声 in-band noise带通滤波器 band-pass filter带外发射 out-of-band emission带外功率 out-of-band power带外衰减 attenuation outside a channel带外信令 out-band signalling带状线 stripline单边带发射 single sideband (SSB) emission单边带发射机 single side-band (SSB) transmitter单边带调制 single side band modulation单边带解调 single side band demodulation单边带信号发生器 single side band signal generaltor单端同步 single-ended synchronization单工、双半工 simplex, halfduplex单工操作 simplex operation单工无线电话机 simplex radio telephone单呼 single call单频双工 single frequency duplex单频信令 single frequency signalling单相对称控制 symmetrical control (single phase)单相非对称控制 asymmetrical control (single phase)单向 one-way单向的 unidirectional单向控制 unidirectional control单信道地面和机载无线电分系统 SINCGARS单信道无绳电话机 single channel cordless telephone单信号方法 single-signal method单音 tone单音脉冲 tone pulse单音脉冲持续时间 tone pulse duration单音脉冲的单音频率 tone frequency of tone pulse单音脉冲上升时间 tone pulse rise time单音脉冲下降时间 tone pulse decay time单音制 individual tone system单元电缆段（中继段） elementary cable section (repeater section)单元再生段 elementary regenerator section (regenerator section)单元增音段，单元中继段 elementary repeater section当被呼移动用户不回答时的呼叫转移 call forwarding on no reply (CFNRy)当被呼移动用户忙时的呼叫转 calling forwarding on mobile subscriber busy (CFB)当漫游到原籍PLMN国家以外时禁止所有入呼 barring of incoming calls when roaming outside the home PLMN country (BIC-Roam)当前服务的基站 current serving BS当无线信道拥挤时的呼叫转移calling forward on mobile subscriber not reachable (CENRc)刀型天线 blade antenna导频 pilot frequency导频跌落pilot fall down倒L型天线 inverted-L antenna等步的 isochronous等幅电报 continuous wave telegraph等权网（互同步网） democratic network (mutually synchronized network) 等效比特率 equivalent bit rate等效地球半径 equivalent earth radius等效二进制数 equivalent binary content等效全向辐射功率 equivalent isotropically radiated power (e. i. r. p.) 等效卫星线路躁声温度 equivalent satellite link noise temperature低轨道卫星系统 LEO satellite mobile communication system低气压实验 low atmospheric pressure test低时延码激励线性预测编码 low delay CELP (LD-CELP)低通滤波器 low pass filter低温实验 low temperature test低躁声放大器 low noise amplifier地-空路径传播 earth-space path propagation地-空通信设备 ground/air communication equipment地波 ground wave地面连线用户 land line subscriber地面无线电通信 terrestrial radio communication地面站（电台） terrestrial station第N次谐波比 nth harmonic ratio第二代无绳电话系统 cordless telephone system second generation (CT-2) 第三代移动通信系统 third generation mobile systems点波束天线 spot beam antenna点对地区通信 point-area communication点对点通信 point-point communication点至点的GSM PLMN连接 point to point GSM PLMN电报 telegraphy电报电码 telegraph code电波衰落 radio wave fading电池功率 power of battery电池能量 energy capacity of battery电池容量 battery capacity电池组 battery电磁波 electromagnetic wave电磁波反射 reflection of electromagnetic wave电磁波饶射 diffraction of electromagnetic wave电磁波散射 scattering of electromagnetic wave电磁波色射 dispersion of electromagnetic wave电磁波吸收 absorption of electromagnetic wave电磁波折射 refraction of electromagnetic wave电磁场 electromagnetic field电磁发射 electromagnetic field电磁辐射 electromagnetic emission电磁干扰 electromagnetic interference (EMI)电磁感应 electromagnetic induction电磁环境 electromagnetic environment电磁兼容性 electromagnetic compatibility (EMC)电磁兼容性电平 electromagnetic compatibility level电磁兼容性余量 electromagnetic compatibility margin 电磁脉冲 electromagnetic pulse (EMP)电磁脉冲干扰 electromagnetic pulse jamming电磁敏感度 electromagnetic susceptibility电磁能 electromagnetic energy电磁耦合 electromagnetic coupling电磁屏蔽 electromagnetic shielding电磁屏蔽装置 electromagnetic screen电磁骚扰 electromagnetic disturbance电磁噪声 electromagnetic noise电磁污染 electromagnetic pollution电动势 electromotive force (e. m. f.)电话机 telephone set电话局容量 capacity of telephone exchange电话型电路 telephone-type circuit电话型信道 telephone-type channel电离层 ionosphere电离层波 ionosphere wave电离层传播 ionosphere propagation电离层反射 ionosphere reflection电离层反射传播 ionosphere reflection propagation电离层散射传播 ionosphere scatter propagation电离层折射 ionosphere refraction电离层吸收 ionosphere absorption电离层骚扰 ionosphere disturbance电流探头 current probe电路交换 circuit switching电屏蔽 electric shielding电视电话 video-telephone, viewphone, visual telephone 电台磁方位 magnetic bearing of station电台方位 bearing of station电台航向 heading of station电文编号 message numbering电文队列 message queue电文格式 message format电文交换 message switching电文交换网络 message switching network电文结束代码 end-of-message code电文路由选择 message routing电小天线 electronically small antenna电信管理网络 telecommunication management network (TMN)电信会议 teleconferencing电压变化 voltage change电压变化持续时间 duration of a voltage change电压变化的发生率 rate of occurrence of voltage changes电压变化时间间隔 voltage change interval电压波动 voltage fluctuation电压波动波形 voltage fluctuation waveform电压波动量 magnitude of a voltage fluctuation电压不平衡 voltage imbalance, voltage unbalance电压浪涌 voltage surge电压骤降 voltage dip电源 power supply电源电压调整率 line regulation电源抗扰性 mains immunity电源持续工作能力 continuous operation ability of the power supply 电源去耦系数 mains decoupling factor电源骚扰 mains disturbance电子干扰 electronic jamming电子工业协会 Electronic Industries Association (EIA)电子系统工程 electronic system engineering电子自动调谐 electronic automatic tuning电子组装 electronic packaging电阻温度计 resistance thermometer跌落试验 fall down test顶部加载垂直天线 top-loaded vertical antenna定长编码 block code定期频率预报 periodical frequency forecast定时 clocking定时超前 timing advance定时电路 timing circuit定时恢复（定时抽取） timing recovery (timing extration)定时截尾试验 fixed time test定时信号 timing signal定数截尾试验 fixed failure number test定向天线 directional antenna定型试验 type test动态频率分配 dynamic frequency allocation动态信道分配 dynamic channel allocation动态重组 dynamic regrouping动态自动增益控制特性 dynamic AGC characteristic抖动 jitter独立边带 independent sideband独立故障 independent fault端到端业务 teleservice短波传播 short wave propagation短波通信 short wave communication短路保护 short-circuit protection短期抖动指示器 short-term flicker indicator短期频率稳定度 short-term frequency stability短时间中断（供电电压） short interruption (of supply voltage)段终端 section termination对称二元码 symmetrical binary code对地静止卫星 geostationary satellite对地静止卫星轨道 geostationary satellite orbit对地同步卫星 geosynchronous satellite对讲电话机 intercommunicating telephone set对空台 aeronautical station对流层 troposphere对流层波道 troposphere duct对流层传播 troposphere propagation对流层散射传播 troposphere scatter propagation多次调制 multiple modulation多点接入 multipoint access多电平正交调幅 multi-level quadrature amplitude modulation (QAM) 多分转站网 multidrop network多服务器队列 multiserver queue多工 multiplexing多工器 nultiplexer多功能系统 MRS多级处理 multilevel processing多级互连网络 multistage interconnecting network多级卫星线路 multi-satellite link多径 multipath多径传播 multipath propagation多径传播函数 nultipath propagation function多径分集 multipath diversity多径时延 multipath delay多径衰落 multipath fading多径效应 multipath effect多路复接 multiplexing多路接入 multiple access多路信道 multiplexor channel多脉冲线性预测编码 multi-pulse LPC (MPLC)多频信令 multifrequency signalling多普勒频移 Doppler shift多跳路径 multihop path多信道选取 multichannel access (MCA)多信道自动拨号移动通信系统multiple-channel mobile communication system with automatic dialing 多优先级 multiple priority levels多帧 multiframe多址呼叫 multiaddress call多址联接 multiple access多重时帧 multiple timeframe多用户信道 multi-user channeltranslatorcz (2007-2-03 13:48:55)E额定带宽 rated bandwidth额定射频输出功率 rated radio frequency output power额定使用范围 rated operating range额定音频输出功率 rated audio-frequency output power额定值 rated value爱尔兰 erlang恶意呼叫识别 malicious call identification (MCI)耳机（受话器） earphone耳机额定阻抗 rated impedance of earphone二十进制码 binary-coded decimal (BCD) code二十进制转换 binary-to-decimal conversion二十六进制转换 binary-to-hexadecimal conversion二进制码 binary code二进制频移键控 binary frequency shift keying (BFSK)二进制数 binary figure二频制位 binary digit(bit)二频制 two-frequency system二维奇偶验码 horizontal and vertical parity check code二线制 two-wire system二相差分相移键控 binary different phase shift keying (BDPSK)二相相移键控 binary phase shift keying (BPSK)F发报机 telegraph transmitter发射 emisssion发射（或信号）带宽 bandwidth of an emission (or a signal)发射机 transmitter发射机边带频谱 transmitter sideband spectrum发射机额定输出功率 rated output power of transmitter发射机合路器 transmitter combiner发射机冷却系统 cooling system of transmitter发射机启动时间 transmitter attack time发射机效率 transmitter frequency发射机杂散躁声 spurious transmitter noise发射机之间的互调 iner-transmitter intermodulation发射机对答允许频（相）偏transmitter maximum permissible frequency(phase) deviation 发射类别 class of emission发射频段 transmit frequency band发射余量 emission margin发送 sending发送响度评定值 send loudness rating (SLR)繁忙排队/自动回叫 busy queuing/ callback反馈控制系统 feedback control system反射功率 reflection power反射卫星 reflection satellite反向话音通道 reverse voice channel (RVC)反向控制信道 reverse control channel (RECC)泛欧数字无绳电话系统 digital European cordless telephone 方舱 shelter方向性系数 directivity of an antenna防爆电话机 explosion-proof telephone set防潮 moisture protection防腐蚀 corrosion protection防霉 mould proof仿真头 artificial head仿真耳 artificial ear仿真嘴 artificial mouth仿真天线 dummy antenna放大器 amplifier放大器线性动态范围 linear dynamic range of amplifier放电 discharge放电电压 discharge voltage放电深度 depth of discharge放电率 discharge rate放电特性曲线 discharge character curve非等步的 anisochronous非归零码 nonreturn to zero code (NRZ)非均匀编码 nonuniform encoding非均匀量化 nonuniform quantizing非连续干扰 discontinuous disturbance“非”门 NOT gate非强占优先规则 non-preemptive priority queuing discipline非受控滑动 uncontrolled slip非线性电路 nonlinear circuit非线性失真 nonliear distortion非线性数字调制 nonlinear digital modulation非占空呼叫建立 off-air-call-set-up (OACSU)非专用控制信道 non-dedicated control channel非阻塞互连网络 non-blocking interconnection network分贝 decibel (dB)分辨力 resolution分布参数网络 distributed parameter network分布式功能 distributed function分布式数据库 distributed database分别于是微波通信系统 distributed microwave communication system分布式移动通信系统 distributed mobile communication system分布路线 distribution link分段加载天线 sectional loaded antenna分机 extension分集 diversity分集改善系数 diversity improvement factor分集间隔 diversity separation分集增益 diversity gain分集接收 diversity reception分接器 demultiplexer分频 frequency division分散定位 distributed channel assignment分散控制方式 decentralized control分散式帧定位信号 distributed frame alignment signal分同步（超同步）卫星 sub-synchronous (super-synchronous) satellite 分谐波 subharmonic分组交换 packet switching分组码 block code分组无线网 packet radio network分组循环分散定位 block cyclic distributed channel assigment分组组装与拆卸 packet assembly and disassembly封闭用户群 closed user group (CUG)峰包功率 peak envelop power峰值 peak value峰值-波纹系数 peak-ripple factor峰值包络检波 peak envelop detection峰值功率 peak power峰值功率等级（移动台的） peak power class (of MS)峰值检波器 peak detector峰值限制 peak limiting蜂窝手持机 cellular handset蜂窝系统 cellular system缝隙天线 slot antenna服务基站 serving BS服务访问点 service access point (SAP)服务弧 service arc服务可保持性 service retainability服务可得到性 service accessibility服务提供部门 service provider服务完善性 service integrity服务小区 serving cell服务易行性 service operability服务支持性 service supportability服务质量 quality of service服务准备时间 service provisioning time符号率 symbol rate幅度检波 amplitude detection幅度量化控制 amplitude quantized cntrol幅度失真 amplitude distortion幅度调制 amplitude modulation (AM)幅频响应 amplitude-frequency response幅相键控 amplitude phase keying (APK)辐射 radiation辐射单元 radiating element辐射方向图 radiation pattern辐射干扰 radiated interference辐射近场区 radiating near-field region辐射能 radiant energy辐射强度 radiation intensity辐射区 radiated area辐射实验场地 radiation test site辐射效率 radiation efficiency辐射源（电磁干扰） emitter (of electromagnetic disturbance)辐射杂散发射 radiated spurious emission辐射阻抗 radiation impedance俯仰角 pitch angle负极 negative electrode负离子 negative ion负荷容量（过荷点） load capacity (overload point)负逻辑 negative logic负码速调整（负脉冲塞入） negative justification (negative pulse stuffing) 负载调整率 load regulation负阻放大器 negative resistance amplifier负阻效应 negative resistance effect负阻振荡 negative resistance oscillation附加符号 additional character附加位 overhead bit复合音 complex sound复接器 multiplexer复节-分接器 muldex复接制 multiple connection system复位 reset复用转接器 transmultiplexer复帧 multiframe副瓣 minor lobe副瓣电平 minor level覆盖区（一个地面发射台的） coverage area (of a terrestrial transmitting station)G概率 probability概率分布 probability distribution概率信息 probabilistic information概率译码 probabilistic decoding干扰 interference干扰参数 interference parameter干扰限值 limit of interference干扰信号 interfering signal干扰抑制 interfering suppression干扰源 interfering resource干线 trunk line感应近场区 reactive near-field region港口操作业务 port operation service港口电台 port station港口管理系统 harbor management system港口交通管理系统 harbor traffic control system高[低]电平输出电流 high (low)-level output current高[低]电平输出电压 high (low)-level output voltage高波 high-angle ray高层功能 high layer function高层协议 high layer protocol高级数据链路控制规程 high level data link control (HDLC) procedure高级通信业务 advanced communication service高级研究计划署 Advanced Research Projects Agency (ARPA)高级移动电话系统 Advanced Mobile Phone System (AMPS)高频放大器 high frequency amplifier高频提升 high frequency boost高频增益控制 high frequency gain control高斯信道 Gauss channel (AWG)高斯最小频移键控 Guassian minimum shift keying (GMSK)高频制频率时的发射频偏 transmitting frequency deviation of high frequency 高通滤波器 highpass filter高温高湿偏置试验 high temperature high humidity biased testing (HHBT)高温功率老化 burning高温试验 high temperature test告警接收机 warning receiver告警指示信号 alarm indication signal (AIS)戈莱码 Golay code戈帕码 Goppa codes格码调制 trellis codes modulation schemes (TCM)隔离放大器 isolation amplifier个人数字助理 personal digital assistant (PDA)个人电台 personal station (PS)个人电台系统 personal radio system个人识别号码 personal identification number (PIN)个人通信 personal communications个人通信网 personal communication networks (PCN)个人携带电话 personal handy phone (PHP)个人移动性 personal mobility个体接收（在卫星广播业务中） individual reception跟踪保持电路 track and hold circuit跟踪带宽 tracking bandwidth更改地址插入 changed address interception工科医用（的） ISM工科医用频段 ISM frequency band工业干扰 industrial interference工作最高可用频率 operational MUF工作比 duty cycle工作范围 working range工作频率范围 operating frequency range工作站 work station (WS)工作周期 cycle of operation公共分组交换网 public packet switched network公共耦合点 point of common coupling (PCC)公开密匙体制 public key system公路交通管制系统 highway traffic control system公用数据网 public data network公众陆地移动电话网 public land mobile network (PLMN)功能键 function key功能群，功能群令 function group, function grouping功率合成 power synthesis功能控制报文 power control message功率控制电平 power control level功率谱密度 power spectrum density功率损耗 power loss功率因子 power factor供电系统阻抗 supply system impedance共道抑制 co-channel suppression共道信令 co-channel signalling共模电压，不平衡电压 common mode voltage, asymmetrical voltage 共模电流 common mode current共模转换 common code conversion共模干扰 common code interference共模抑制比 common code rejection ratio (CMRR)共模增益 common mode gain共模阻抗 common code impedance共信道再用距离 co-channel re-use distance贡献路线 contribution link固定电台 fixed station固定基地电台 fixed base station固定信道指配 fixed channel assignment固态发射机 solidstate transmitter固有可靠性 inherent reliability固有频差 inherent frequency error故障 fault故障安全 fault safe故障保护 fault protection故障弱化 failsoft故障修复 fault correcting故障原因 fault cause故障准则 fault criteria挂机信号 hang-up signal管理中心 administration center (ADC)广播控制信道（BCCH）划分 BCCH allocation (BA)广播寻呼系统 broadcast paging system广域网 wide area network (WAN)归零码 return to zero code (RZ)归一化的偏置 normalized offset规程 protocol规范 specification规则脉冲激励编码 regular-pulse excitation (RPE)规则脉冲激励长时预测编码 regular-pulse excitation LPC (RPE-LPC) 轨道 orbit国际标准 international standard国际单位制 international system of units国际电报电话咨询委员会 CCITT国际电工委员会 IEC国际电信联盟 ITU国际互连网 Internet国际民航组织 ICAO , international civil aviation organization国际通信卫星组织 INTERAT国际海事卫星组织 INMAR-SAT国际无线电干扰特别委员会 CISPR国际无线电干扰委员会 CCIR国际移动识别码 international mobile station equipment identity (IMEI) 国际移动用户识别码 international mobile subscriber identity (IMSI)国际原子时间 international automatic time (TAI)国家标准 national standard国家信息基础结构 national information infrastructure (NII)过充电 overcharge过滤带 transition band过放电 overdischarge过荷保护电路 overload protecting circuit过荷分级控制 overload control category过荷控制 overload control过调制 overmodulation过流保护 overcurrent protection过压保护 overvoltage protectiontranslatorcz (2007-2-03 13:50:12)H海岸地球站 coast earth station海岸电台 coast station海事卫星通信 maritime satellite communications汉明距离 Hamming distance汉明码 Hamming code汉明重量 Hamming weight航空地球站 aeronautical earth station航空电台 aeronautical station航空器地球站 aircraft earth station航空器电台 aircraft station航空移动业务 aeronautical mobile service航天器（宇宙飞船） spacecraft毫米波 millimeter wave黑格巴哥码 Hagelbarger code恒比码 constant ratio code恒步的 homochronous恒流电源 constant current power supply恒温恒湿试验 constant temperature and humid test恒压充电 constant voltage charge恒压电源 constant voltage power supply恒电磁波小室 transverse electromagnetic wave cell (TEM cell)喉式传声器 throat microphone后瓣 back hole厚模电路 thick-film circuit呼叫 call呼叫支持 call hold (HOLD)呼叫存储 call store呼叫等待 call waiting (CW)呼叫改发 call redirection呼叫建立 call establishment呼叫建立时间 call set-up time呼叫接通率 percept of call completed呼叫控制信号 call control signal呼叫清除延时 call clearing delay呼叫释放 call release呼叫序列 calling sequence呼叫转移 call transfer (CT)呼救 distress call呼救系统 distress system呼损率 percept of call lost呼通概率 calling probability互补金属氧化物半导体集成电路complementary MOS integrated circuit (COMOS-IC)互连 interworking互连的考虑 interworking consideration互连功能 interworking function (IWF)互调 intermodulation互调产物（一个发射台的） intermodulation products (of a transmitting stastion) 互调抗扰性 intermodulation immunity互调失真 intermodulation distortion互通性 interoperability互同步网 mutually synchronized network话路输入电平 voice circuit input level话路输入电平差异 voice circuit input level difference话务量 telephone traffic话音活动检测 voice activity detection (VAD)话音激活 voice exciting话音激活率 speech activity话音数字信令 speech digit signalling话音突发 speech spurt环境试验 environment test环境系数 environment factor环境应力筛选 environment stress screening (ESS)环境躁声 ambient noise环路传输 loop transmission环路高频总增益 loop RF overall gain环路可锁定最底（最高）界限角频率loop lockable minimum (maximum) margin angular frequency环路滤波器比例系数 loop filter proportion coefficient环路躁声带宽 loop noise bandwidth环路增益 loop gain环路直流总增益 loop DC overall gain环路自然谐振角频率 loop natural resonant angular frequency环形波 ring wave环形混频器 ring mixer环行器 circulator环行延迟 rounding relay恢复 recovery恢复规程 restoration procedure汇接交换 tandem switching汇接局 tandem office会话（在电信中） conversation (in telecommunication)会话层 session layer会议电话 conference telephone混合ARQ hybrid ARQ混合差错控制 hybrid error control (HEC)混合分集 hybrid diversity混合集成电路 hybrid integrated circuit混合扩频 hybrid spread spectrum混合路径传播 mixed-path propagation混合信道指配 hybrid channel assignment混频器 mixer混频器的寄生响应 mixer spurious response活动模式 active mode“或”门 OR gate“或非”门 NOR gateJ机壳辐射 cabinet radiation机载电台 aircraft station基本传输损耗（无线线路的） basic transmission loss (of a radio link) 基本接入 basic access基本业务（GSM的） basic service (of GSM)基本越区切换规程 basic handover procedure基本最高可用频率 basic maximun usable frequency基波（分量） fundamental (component)基波系数 fundamental factor基带 baseband基地（海岸）（航空）设备 base (coast)(aeronautical) equipment基地电台 base station (BS)基站控制器 base station controller (BSC)基站识别码 base station identity code (BSIC)基站收发信台 base transceiver station (BTS)基站系统 base station system (BSS)基站区 base station area基准条件 reference condition基准阻抗 reference impedance奇偶校验码 parity check code奇偶校验位 parity bit激活 activation吉尔伯特码 Gilbert code级联码 concatenated code即时业务 demand service急充电 boost charge急剧衰落 flutter fading集成电路 integrated circuit集成电路卡 integrated circuit card集群电话互连 trunked telephone connect集群电话互连器 trunked telephone connector集群基站 trunked base station集群效率 trunking efficiency集群移动电话系统 trunked mobile communication system集体呼叫 group call集体接收（在卫星广播业务中） community reception集中控制方式 centralized control集中式帧定位信号 bunched frame alignment signal计费信息 advice of charge计算机病毒 computer virus计算机辅助测试 computer-aided test (CAT)计算机辅助工程 computer-aided engineering (CAE)计算机辅助管理 computer-aided management (CAM)计算机辅助教学 computer-aided instruction (CAU)计算机辅助设计 computer-sided design (CAD)寄生反馈 parasitic feedback寄生调制 parasitic modulation寄生振荡 parasitic oscillation加密 encipherment加密保护 encipherment protection加密方案 encipherment scheme加权（互同步）网 hierarchic (mutually synchrohous) network 假负载 dummy load假设参考电路 hypothetical reference circuit尖峰信号 spike间接分配 indirect distribution间接调频 indirect frequency modulation监测音峰频偏 supervisory audio tone peak deviation监测音频单音 supervisory audio tone (SAT)兼容话 compatible telephone兼容性 compatibility检波器的充电时间常数 electrical charge time constant of a detector检波器的电流灵敏度 detector current sensitivity检波器的电压灵敏度 detector voltage sensitivity检波器的放电时间常数 electrical discharge time constant (of a detector) 检波失真 detection distortion检波效率 detection efficiency检错 error detection检错反馈系统 error-detecting and feedback system检错码 error detecting code检错能力 error-detecting capacity减载波单边带发射 reduced carrier SSB emission减载波发射 reduced carrier emission减振器 damper, antivibrator剪音 clipping建筑物穿透损耗 building penetration loss鉴定测试 characterization test鉴权中心 authentication center (AUC)鉴频器 frequency discriminator鉴相鉴频器 phase detection discriminator鉴相灵敏度 discriminator sensitivity鉴相器 phase discriminator鉴相器输出误差电压 discriminator output error voltage键控 keying键盘 keyboard降额 derating降级 degradation降灵 desensitization降落物散射传播 precipitation scatter propagation交变温热试验 alternate humid heat test交叉干扰 cross interference交叉失真 cross-over distortion交换机无线接口 exchange radio interface交换局 exchange交换连接 switched connection交换区 switched area交流声 hum交替代号反转码 alternate mark inversion code (AMI code)交替信号反转破坏点（双极性破坏点）alternate mark inversion violation (bipolar violation)交调 cross-modulation角度分集 angle diversity角度调制 angle modulation角反射天线 corner reflector antenna校验位 check bit校验字符 check character校准 calibration接地 grounding接地电感线圈 earth inductor接口标准 interface standard接口集成电路 interface integrated circuit接口结构 interface structure接入能力 access capability接入争用 access contention接入信道 access channel接收机 receiver接收机保护装置 receiver protector接收机的过载系数 overload factor of receiver接收机动态范围 receiver dynamic range接收机分路器 receiver multi-coupler接收机门限电平 receiver threshold-signal level接收机前端 front-end of receiver接收至发射的回波耗损 receive to transmit echo loss (RTEL)接收至发射的稳定耗损 receive to transmit stability loss (RTSL)接收响度评定值 receive loudness rating (RLR)接线信号 connect signal接续（连接） connection结点 node解码 decoding解码器 decoder解码器保护时间 decoder required protection time解码器报讯时间 decode alarm time解码器的选择性 decoder selectivity解码器工作电平范围 decoder operate level range解码器恢复时间 decoder recovery time解码器启动时间 decoder attack time解码器假码虚报 decoder false code falsifying解码器噪声虚报 decoder noise falsifying解密 decipher解扰器 descrambler解调 demodulation解调载频控制 demodulation carrier frequency control紧急呼叫 emergency call紧急指位无线信标台 emergency position-indicating rediobeacon station。
马尔文激光粒度仪简介
laParticle size analysis-Laser diffraction methods(ISO-13320-1)IntroductionLaser diffraction methods are nowadays widely used for particle sizing in many different applications. The success of the technique is based on the tact that it can be applied to various kinds of particulate systems, is fast and can be automated and that a variety of commercial instruments is available. Nevertheless, the proper use of the instrument and the interpretation of the results require the necessary caution.Therefore, there is a need for establishing an international standard for particle size analysis by laser diffraction methods. Its purpose is to provide a methodology for adequate quality control in particle size analysis.Historically, the laser diffraction technique started by taking only scattering at small angles into consideration and, thus, has been known by the following names:-fraunhofer diffraction;-(near-) forward light scattering;-low-angle laser light scattering (LALLS).However, the technique has been broadened to include light scattering in a wider angular range and application of the Mie theory in addition to approximating theories such as Fraunhofer and anomalous diffraction.The laser diffraction technique is based on the phenomenon that particles scatter light in all directions with an intensity pattern that is dependent on particle size. All present instruments assume a spherical shape for the particle. Figure 1 illustrates the characteristics of single particle scattering patterns: alternation of high and low intensities, with patterns that extend for smaller particles to wider angles than for larger particles[2-7,10,15 in the bibliography].Within certain limits the scattering pattern of an ensemble of particles is identical to the sum of the individual scattering patterns of all particles present. By using an optical model to compute scattering for unit volumes of particles in selected size classes and a mathematical deconvolution procedure, a volumetric particle size distribution is calculated, the scattering pattern of which fits best with the measured pattern (see also annex A).A typical diffraction instrument consists of a light beam (usually a laser), a particulate dispersing device, a detector for measuring the scattering pattern and a computer for both control of the instrumentand calculation of the particle size distribution. Note that the laser diffraction technique cannot distinguish between scattering by single particles and scattering by clusters of primary particles forming an agglomerate or an aggregate. Usually, the resulting particle size for agglomerates is related to the cluster size, but sometimes the size of the primary particles is reflected in the particle size distribution as well. As most particulate samples contain agglomerates or aggregates and one is generally interested in the size distribution of the primary particles, the clusters are usually dispersed into primary particles before measurement.Historically, instruments only used scattering angles smaller than 14°,which limited the application to a lower size of about 1μm. The reason for this limitation is that smaller particles show most of their distinctive scattering at larger angles (see also annex Z).Many recent instruments allow measurement at larger scattering angles, some up to about 150°,for example through application of a converging beam, more or larger lenses, a second laser beam or more detectors. Thus smaller particles down to about μm can be sized. Some instruments incorporate additional information from scattering intensities and intensity differences at various wavelengths and polarization planes in order to improve the characterization of particle sizes in the submicrometre range.Particle size analysis – Laser diffraction methods-Part 1:General principles1 scopeThis part of ISO 13320 provides guidance on the measurement of size distributions of particles in any two-phase system, for example powders, sprays, aerosols, suspensions, emulsions and gas bubbles in liquids, through analysis of their angular light scattering patterns. It does not address the specific requirements of particle size measurement of specific products. This part of ISO13320 is applicable to particle sizes ranging from approximately μm to 3μm.For non-spherical particles, an equivalent-sphere size distribution is obtained because the technique uses the assumption of spherical particles in its optical model. The resulting particle size distribution may be different from those obtained by methods based on other physical principles . Sedimentation, sieving).3,terms, definitions and symbolsFor the purposes of this part of ISO 13320, the following terms, definitions and symbols apply.terms, definitionsabsorptionintroduction of intensity of a light beam traversing a medium through energy conversion in the mediumcoefficient of variation (变异系数)Noative measure(%) for precision: standard deviation divided by mean value of population and multiplied by 100 or normal distributions of data the median is equal to the meanrefractive index（Ｎｐ）Refractive index of a particle, consisting of a real and an imaginary (absorption) part.Np=n p-ik prelative refractive index （m）complex refractive index of a particle, relative to that the medium。
专业英语-IT专业英语词汇精选（F2）
其它-专业英语-IT专业英语词汇精选(F2)FM Facility Management 设备管理FM Fast Memory 快速存储器FM Fault Management 故障管理FM Feedback Mechanism 反馈机构FM File Management 文件管理FM fine magic 好戏法〖网语〗FM Flash Memory 瞬间存储器，快闪存储器，快擦型存储器（1980年日本东芝公司发明）FM Forms Management 窗体管理FM Frequency Meter 频率计FM Frequency Modulation 调频FM Function Manager 功能管理器fm Micronesia 密克罗尼西亚（域名）.fm FileMaker Pro的电子表格文件格式〖后缀〗.fm1 Lotus 1-2-3 release 2.x的电子表格文件格式〖后缀〗.fm3 Harvard Graphics 3.0的设备驱动器文件格式〖后缀〗.fm3 Lotus 1-2-3 release 3.x的电子表格文件格式〖后缀〗FM / FDM Frequency Modulation / Frequency Division Multiplex 调频 / 频率分开多路复用FM / FDMA Frequency Modulation / Frequency Division Multiple Access 调频 / 频率分开多路访问FM / TDMA Frequency Modulation / Time Division Multiple Access 调频 / 时间分开多路访问FMA Failure Mode Analysis 故障模式分析.fmb WordPerfect for Win文件管理器按钮棒形图文件格式〖后缀〗FMC Fixed Message Cycle 固定讯号周期FMC Flexible Manufacture Cell 灵活制造单元FMC Force Majeure Clause 不可抗力条款FMC Full duplex Multiple line Control station 全双工多线路控制站FMCH FirMware CHannel 固件通道FMCW Frequency Modulated Carrier Wave 调频载波FMCW Frequency Modulated Continuous Wave 调频等幅波FMD Function Management Data 功能管理数据FMDEM Frequency Modulation DEModulator 频率调制解调器FMDM Frequency Modulation Deviation Meter 调频测偏计FME Frequency – Measuring Equipment 测频装置，频率计FMEA Fault Modes and Effect Analysis 故障模式与结果分析FMF File Microprogram Flags register 文件微程序标志（寄存器）.fmf IBM LinkWay的字体图标文件格式〖后缀〗FMFB Frequency Modulation with Feed Back 反馈调频FMFF Frequency Modulation Feed Forward 调频前馈FMG Frequency Modulation Generator 频率调制发生器FMI Fast Multimedia Inc. 快速多媒体公司（美国，出品视频捕获卡）FMIC Frequency Monitoring and Interference Control 频率监听与干扰控制器FMID Function Modification IDentifier 功能修改标识符FMIS Finance Management Information System 金融管理信息系统.fmk Fortran PowerStation的文件编写格式〖后缀〗FML File Manipulation Language 文件操作语言FML Floating MuLtiply 浮点乘法FMLI Form and Menu Language Interpreter 表单菜单语言解释程序〖UNIX〗FMLP Fuzzy Multilayered Perception 模糊多层感知器FMM Flat Memory Model 平面内存模型FMM Modified Frequency Modulation 改进的频率调制.fmo dBase IV的编译文件格式〖后缀〗FMP Flow Management Protocol 流程管理协议FMPD Frequency – Modulation Predistortion 调频预失真FM-PM Frequency Modulation – Phase Modulation 调频－调相FMPP Flexible MultiPipeline Processor 多流水线软处理器FMR Facility Management Reporting 设施管理报告FMR Frequency Modulated Radar 调频雷达FMR Frequency Modulated Receiver 调频接收机FMS Facsimile Mail System 传真邮件系统FMS Fiber Management System 光纤管理系统FMS File Management System 文件管理系统FMS Financial Management System 财务管理系统FMS Flexible Manufacturing System 柔性制造系统FMS Fly Management System 飞行管理系统FMS FM Screening 散乱抖动〖打印机〗FMS Fortran Monitor System 公式翻译程序监视系统FMS Frequency Measuring Station 测频站FMS Frequency Modulation Synthesis 调频合成〖声卡〗.fmt FOXBASE的屏幕格式文件〖后缀〗.fmt Sprint的样式表文件格式〖后缀〗FMT Frequency Modulated Transmitter 调频发射机FMU File Memory Unit 文件存储单元FMV Full – Motion Video 全动视频，满帧速率电视FMV 富士通微机系列〖品牌〗FMVFT Frequency Modulated Voice Frequency Telegraph 调频音频电报FN Feedback Network 反馈网络FN Frame Number 帧编号FN Function Network 功能网络.fn3 Harvard Graphics 3.0的字体文件格式〖后缀〗FNA Free Network Address 网络空址FNA Fujitsu Network Architecture 富士通网络体系结构FNAE Free Network Address Element 网络空址要素FNB File Name Block 文件名称块FNB Flexible Network Bus 灵活性网络总线FNC Federal Networking Council 联邦网络化委员会（美国）FNI Firefly Networks Inc. “萤火虫”网络公司（美国，协作过滤技术的领导者，出品联机服务系统）FNP Front end Network Processor 前端网络处理器FNPA Foreign Numbering Plan Area 国外编号规划区FNR Fast Network Reconfiguration 快速网络重配置FNS Failure Notification Sheet 故障通知单FNS Federated Naming Service 联合命名服务FNS Feedback Node Set 反馈节点集FNS File Nesting Store 文件嵌套存储FNS Functional Nomenclature Signal 功能命名原则信号FNT FoNT 字体.fnt Bazier（贝氏）类型的字体文件格式〖后缀〗.fnx Exact的不活动字体文件格式〖后缀〗FO Fade Out 淡出，渐逝fo Faroe Island 法罗群岛（域名）FO Fiber Optic 光纤FO Frame Offset 帧偏移量.fo1 Borland Turbo C的字体文件格式〖后缀〗.fo2 Borland Turbo C的字体文件格式〖后缀〗FOA Fiber Optic Amplifier 光纤放大器FOAF Friend Of A Friend 朋友的朋友FOB Fiber Optics Bundle 光纤束FOBS Fiber Optic BoreScope 光纤管道镜FOC Fiber Optic Cable 光缆FOC Fiber Optic Communication 光纤通信FOC Fiber Optic Coupler 光纤耦合器FOCA Font Object Content Architecture 字体对象内容体系结构FOCC Forward Control Channel 前方控制通道FOCH FOrward CHannel 前方通道FOCIS Fiber Optics Communication and Information Society 光纤通信和信息协会FOCIS Financial On – line Customer Information System 金融联机用户信息系统FOCS Fiber Optic Communication System 光纤通讯系统focus 焦点网（首家由美国公司EnReach在中国投资经营的中文网站，1999，9）〖域名〗FOCUS Federation On Computing in the United State 美国计算联盟（国际信息处理联合会属下）FOCUS Fiber Optic Connection Universal System 光纤连接通用系统FOD Fax On Demand 传真求用系统FOD Formulas for Object Definition 对象定义公式FOD Function Operational Design 功能操作设计FODL Fiber Optic Delay Line 光纤延迟线FOG Fiber Optic Gyroscopes 光纤陀螺仪FOG Frequency Offset Generator 频率偏移发生器FOG-M Fiber Optic Guided Missile 光纤制导导弹FOG-V Fiber Optic Guided Vehicle 光纤制导运载工具FOI Fiber Optic Isolator 光纤隔离器FOIA Freedom Of Information Act 信息自由法案FOIL File – Oriented Interpretive Language 面向文件的解释语言，Foil 语言FOIRL Fiber Optic Inter Repeater Link 光纤的转发器间连接，中继器间的光纤链路FOIS Fiber Optic Interferometric Sensor 光纤干涉仪传感器FOL Fiber Optic Laser 光纤激光器.fol 1st Reader的保存信息文件夹格式〖后缀〗FOLAN Fiber Optic Local Area Network 光纤局域网FOM Fiber Optic Modem 光纤调制解调器FOMA Fiber Optic Medium Attachment 光纤媒体附加FOMDI Fiber Optic Medium Dependent Interface 光纤媒体从属接口FON Fiber Optic Net 光纤网.fon 字体文件格式〖后缀〗，电话簿文件格式〖后缀〗.fon Telix的拨号工商名录文件格式〖后缀〗.fon ProComm Plus的呼叫全程记录文件格式〖后缀〗FOOPS Functional Object – Oriented Programming System 面向功能对象的编程系统FOPEN File OPEN 文件打开FOPMA Fiber Optic Physical Medium Attachment 光纤物理媒体附加FOPT Fiber Optic Photo Transfer 光纤照片传送.for FORTRAN语言的源码文件格式〖后缀〗.for WindowBase的表单文件格式〖后缀〗FOREX FOReign EXchange 外汇FORM Fault Occurrence and Repair Models 故障发生和修理模型FORMAC Fiber Optic Ring Media Access Controller 光纤环媒体访问控制器FORMAL Formula manipulation Language 公式处理语言，Formal 语言format DOS外部命令：格式化软硬盘FORMAT FORtran Matrix Abstraction Technique Fortran语言矩阵提取技术FormatC “格式化C盘”：〖Word宏病毒〗FORMS Fiber Optic Reflect Memory System 光纤反射存储系统FORR Fiber Optic Ring Resonator 光纤环形共振器FORTRAN Formula Transformation 公式转换FORTRAN Formula Translation 公式翻译程序FORTRAN Formula Translator 公式翻译程序语言，Fortran 语言（微软于1977年开始发售）FOS File Organization System 文件组织系统FOS Follow – On Support 接续支持FOS FORTRAN Operating System FORTRAN操作系统FOS Function Operational Specification 功能操作说明FOSDIC Film Optical Scanning Device for Input to Computers 用于计算机输入的胶片光学扫描装置FOSI Formatting Output Specification Instance 格式化输出规格实例FOT Fiber Optics cathode ray Tube 光纤阴极射线管FOT Forward Transfer 向前传送FOT Frequency of Optimum Traffic 最佳通信量频率FOT Frequency of Optimum Transmission 最佳传输频率.fot True Type 的字库文件格式〖后缀〗FOTC Fiber Optic Trunk Cable 干线光缆，长途光缆FOTLAN Fiber Optic Tactical Local Area Network 光纤战术局域网FOTM Fiber Optic Test Method 光纤测试方法FOTN Fiber Optic Transmission Network 光纤传输网络FOTP Fiber Optic Test Procedure 光纤测试规程FOTS Fiber Optic Transmission System 光纤传输系统FOTSLH Fiber Optic Transmission System for Long Haul 远程光纤传输系统Founder 方正电脑，北大方正four 11 “411”：因特网的著名寻人网点，1998年并入雅虎〖域名〗Four Phase 四象限公司（美国，1969年推出第一个商用微处理器）FOV Field Of View 视图域.fox FOXBASE的伪编译程序文件〖后缀〗FOX Interactive 福克斯电影公司的多媒体部，专出影视剧软件（世界著名娱乐光盘制造商）FoxWeb “狐网”（数据程序交互使用工具）〖软件名〗FP Fabry – Pero Laser 法布里－泊罗激光器FP File Protect 文件保护FP Floating Point 浮点FP Function Processor 函数处理器FP Functional Programming 函数式编程语言.fp FoxPro的配置文件格式〖后缀〗FPA Failure Probability Analysis 故障概率分析FPA Fixed Point Arithmetic 定点算法FPA Flat Plane Antenna 平面天线FPA Floating-Point Accelerator 浮点加速器FPA Floating Point Arithmetic 浮点算法FPC File Parity Checks 文件奇偶校验FPC Fixed Point Calculation 定点计算FPC Fixed Program Computer 固定程序计算机FPC Forward Propagation Circuit 前推式传播线路FPC Full duplex Point to point Control station 全双工点到点控制站FPC Functional Processor Cluster 发挥作用的处理器簇.fpc FoxPro的目录文件格式〖后缀〗FPD Flat Panel Display 平面显示器FPD Full – Page Display 全页显示FPDS Federal Procurement Data System 联邦政府采购数据系统FPF Facility Parameter Field 设备参数域FPFU Fuji Photo Film USA Inc. 富士胶卷美国公司（出品数字相机）FPGA Field Programmable Gate Array 现场可编程门阵列FPIN Foreign Personal Identification Number 外来个人识别号码FPIS Forward Propagation by Ionospheric Scatter 电离层散射的向前传播FPL Floyd Evans Production Language 弗洛伊德·伊万斯的生成语言FPL Foxbord Programming Language Foxbord的程序设计语言FPL Frequency Phase Lock 频率锁相FPLA Field Programmable Logic Array 现场可编程逻辑阵列FPLMTS Future Public Land Mobile Telecommunication System 未来的公众陆地移动远程通信系统（第三代）FPLS Field – Programmable Logic Sequencer 域可编程逻辑音序器FPM Fast Packets Multiplexing 快速信息包多路传输FPM Fast Page Memory 高速页面存储器FPM Fast Page Mode 快页模式，快速页面模式〖奔腾主板〗FPM Fixed – Program Machine 固定程序计算机FPMA Fixed Preassigned Multiple Access 固定预分配多路存取FPML Financial Product Marker Language 金融产品标记语言FPM RAM Fast Page Mode RAM 快页模式随机存取存储器，快速页面模式随机访问存储器FPN Fixed – Pattern Noise 固定样式噪音FPN Fuzzy Petri Nets 模糊佩特里网FPNW File and Print Services For NetWare 用于“网器”的文件打印服务（微软的）FPO Federal Post Office 联邦邮局（德国）FPO For Position Only 只用于定位FPODA Fixed Priority Oriented Demand Assignment 面向固定优先权的请求分配〖多媒体〗FPOP Floating Point Operations Per Second 每秒浮点运算次数F-port Fiber Port 光纤端口FPP Fixed Path Protocol 固定路径协议FPP Floating Point Package 浮点软件包FPP Floating Point Process(or) 浮点处理（器）FPPA Fiber Patch Panel Assembly 光纤接插板装配FPR Fixed Point Representation 定点表示法FPR Fixed Program Receive 固定节目接受FPR Floating Point Register 浮点寄存器FPS Fast Packet Switching 通信包快速转接，快速数据分组交换FPS File / Print Server 文件 / 打印服务器FPS First Person Shooting Game 第一人称视角游戏〖游戏用语〗FPS Fixed Program Send 固定节目发送FPS Floating Point System, inc. 浮点系统公司（美国）FPS Focus Projection and Scanning (deflection system) 聚焦投影与扫描（偏转系统）FPS Fortran Processing System Fortram语言处理系统FPS Frames Per Second 每秒帧数.fpt FoxPro的备注字段文件格式〖后缀〗FPU Floating Point Unit 浮点单元〖处理器〗.fpw FloorPLAN plus for Windows的绘图文件格式〖后缀〗FQ Fair Queuing 公平排队FQ File Qualifier 文件限定词FQDN Fully Qualified Domain Name 正式域名，完全符合标准的域名FQL File Qualifier Length 文件限定词长度FQL Formal Query Language 正式查询语言FR Facility Request 设备请求FR Failure Rate 故障率FR Failure Record 故障记录FR Family of Requirement 必要条件系列FR Fault Recognition 故障识别FR Fault Report 故障报告FR Fault – Resilient 故障后可恢复原状的FR Fill Rate （像素）充填率〖显卡测试〗FR Forced Release 被迫发布FR Forms Registry 表单注册集FR Frame Relay 帧中继，帆分段传输，图文框接力传送（快速分组交换技术）fr France 法国（域名）FR Frequency Range 频率范围FR Frequency Relay 频率替续器FR Frequency Response 频率响应FR Full Rate 全速率FR Function Reference 函数指南FR Function Register 功能寄存器.fr3 dBase IV的重命名dBASE III+文件格式〖后缀〗FRA Failure Rate Average 平均故障率FRA Federal Radio Act 联邦无线电法案FRA File Relative Address 文件相对地址FRA Fixed Radio Access 固定无线接入FRAC Fixed Reservation Access Control 确定预约存取控制FRAC Fractionators Reflux Analog Computer 分馏回流模拟计算机FRAC Frame Relay Access Concentrator 帧中继接入集中器FRAD Frame Relay Access Device 帧中继访问设备，帧中继接入装置FRAD Frame Relay Assembler / Disassembler 帧中继汇编程序 / 反汇编程序FRAM Ferromagnetic RAM 铁磁随机存储器FRAM Functional Requirements Allocation Matrix 功能性需求分配矩阵FRAP Frame Relay Access Probe 帧中继接入探测器FRBS Federal Reserve Bank System 联邦储备银行系统（美国）FRBS Frame Relay Bearer Service 帧中继运载服务FRC Fault Reporting Center 故障报告中心FRC Federal Radio Commission 联邦无线电委员会（美国）FRC Final Routing Center 终极路由选择中心FRC Forward Read Continuous 连续向前读出FRC Functional Redundancy Checking 功能冗余检查FRCMS Frame Relay Congestion Management Scheme 帧中继拥塞管理方案FRD Failure Rate Data 故障率数据FRD Formulas for Relation Definition 关系定义公式FRD Functional Requirements Document 功能要求文件FRDS Failure Resistant Disk Systems 耐故障磁盘系统FRE Fast Routing Engine 快速路由选择引擎FRE Frame Relay Engine 帧中继引擎FRE Frame Relay Exchange 帧中继交换FRED Figure – Reader Electronic Device 图形阅读器电子器件FRED Figure Reading Electronic Device 电子读数器FREE First Ready First Execute 先就绪先执行Freeserve 免费服务公司（英国的网络公司）FREETECH 富基科技（台湾）FREQ-MULT FREQuency MULTiplier 频率倍增器，倍频器FRESA Frame Relay End – System Address 帧中继端系统地址FRESCAN FREquency SCANning 频率扫描FRESCANNAR FREquency SCANNing radAR 频率扫描雷达FRF Frame Relay Forum 帧中继论坛FRF Frame Repetition Frequency 帧重复频率.frf FontMonger的字体文件格式〖后缀〗FR-FR Frame Relay – to – Frame Relay 从帧中继到帧中继.frg dBase IV的未编译报告文件格式〖后缀〗FRI Finite Impulse Response 有限脉冲应答FRICC Federal Research Internet Coordinating Committee 联邦调研因特网协调委员会FRIF Frame Relay Information Field 帧中继信息域FRIL Fuzzy Relational Inference Language 模糊关系推论语言FRINGE File and Report INformation processing GEnerator 文件与报表信息处理生成器FRICC Federal Research Internet Coordinating Committee 联邦科研因特网协调委员会（美国）FRJ Facility ReJect 设备拒绝FRL Frame Representation Language 帧表示语言FRL Function Reference Listings 函数参照表FRM File Request Management 文件请求管理FRM Film Reading Machine 胶片阅读机FRM FRequency Meter 频率计.frm FOXBASE的报表文件格式〖后缀〗.frm dBase IV、Clipper 5和dBFast的报告文件格式〖后缀〗.frm 命令形式的文本文件格式〖后缀〗FRMR FRaMe Reject 帧拒绝.fro dBase IV的编译报告文件格式〖后缀〗FROM Fusible Read Only Memory 可熔断只读存储器.frp PerForm PRO Plus和FormFlow的表单文件格式〖后缀〗FRPI Flux Reversal Per Inch 磁通反转量 / 每英寸FRR Functional Recovery Routines 功能恢复例程FRS Fast Retrieval Storage 快速检索存储体FRS Forward Ready Signal 前方就绪信号FRS Frame Relay Services 帧中继业务FRS Frame Relay Switch 帧中继转换FRS Frame Relay Switcher 帧中继转换器FRS Fundamental Reference System 基本引用系统.frs WordPerfect的屏幕字体资源文件格式〖后缀〗FRSN Frame Relay Switch Node 帧中继转换节点FRT Failure Rate Test 故障率测试.frt FoxPro的报表文件格式〖后缀〗FRTF Fixed Radio Transmission Facility 固定式无线电播送设备FRU Field-Replaceable Unit 域可替换单元.frx FoxPro的报表文件格式〖后缀〗FS FacSimile 传真FS Factor of Safety 安全系数FS False Signal 错误信号FS Fast Select 快选Fs Femto second 飞秒，毫微微秒FS Field Separator 字段分隔符FS Field Strength 场强FS Figure Switch 数字开关FS File Separator 文件分隔符FS File Services 文件服务功能FS File Structure 文件结构FS Final Selector 最终选择器FS Finity State 有限态FS Fixed Station 固定台FS Fixed Subscriber 固定用户FS Floating Sign 浮点符号，浮标FS Follow Shot 随拍，移动拍摄FS Frame Scan 帧扫描FS Frame Status 帧状态FS Frame Store 帧存储FS Frame Switching 帧交换技术〖网络〗FS Frame Synchro 帧同步FS FreeSpace 《自由空间》〖游戏名〗FS Frequency Shift 频移FS Frequency Standard 频率标准FS Frequency Synthesizer 频率合成器FS Full Shot 全景镜头FS Full Status 完整状态FS Function Selection 功能选择FS Functional Symbol 功能符号FSA Frequency Stability Analyzer 频率稳定性分析仪FSAA Full Scene Anti – Aliasing 全景抗锯齿失真（加速芯片的功能）FSB File Cache Buffers 文件高速缓冲存储器缓冲区FSB Forward Space Block 正向间隔块FSB Front Side Bus 前端总线〖芯片组〗FSC Fault Simulation Comparator 故障模拟比较器FSC Fault Symptom Code 故障征兆代码FSC File Security Control 文件安全控制FSC Fixed Size Character 定长字符FSC Frequency Shift Converter 移频转换器FSC Fujitsu Software Corp. 富士通软件公司（日本，出品网络联组件）FSCB File System Control Block 文件系统控制块FSCS Frequency Shift Communication System 频移通信系统FSCS Fundamental Studies in Computer Science 计算机科学基础研究FSD Federal System Division (IBM) 联邦系统分部（属IBM公司）FSD Fixed Shroud Duplex 固定屏板双工操作FSD Full Scale Deflection 满度偏转，满刻度偏差FSDD Fibers with Slowly Decreasing Dispersion 缓降色散光纤FSDS Fairchild Software Development System 以童软件开发系统FSDS File – System Descriptor Set 文件系统描述符集FSE Fractionally Spaced Equalizer 微弱间隔均衡器FSEC Federal Software Exchange Center 联邦软件交易中心（美国）FSF Fixed Sequence Format 固定顺序格式FSF Forward Space File 正向间隔文件FSF Free Software Foundation 自由软件基金会FSG Federated Systems Group 联合系统组FSI Fairchild Semiconductor Inc. “以童”半导体公司（英特尔和AMD的前身）FSI Fault Symptom Index 故障征兆索引FSI Field – Sequential Illumination 场续照明〖投影仪〗FSI Fore Systems Inc. 前部设备系统公司（美国，出品网络适配器）FSI Frequency Subset Indicator 频率子集指示器FSI Funk Software Inc. “臭臭”软件公司（美国，出品网管工具）FSIOP File Server Input / Output Processor 文件服务器输入输出处理器FSIP Federal Security Infrastructure Program 联邦信息安全基础设施计划FSK Frequency – Shift Keying 频移键控FSKNRZ Frequency – Shift Keying, No Return to Zero 频移键控，不归零FSK TP Frequency – Shift Keying TelePrinter 频移键控电传打字机FSL Fast ethernet interSwitch Link 快速以太网互换开关链路FSL Finite State Language 有限状态语言FSL Font Selection Logic 字体选择逻辑FSL Formal Semantic Language 形式语义语言FSL Fujitsu System programming Language 富士通系统程序设计语言（为电子交换系统研制）.fsl Paradox for Windows的表单文件格式〖后缀〗FSLT Fiber Optic Subscriber Line Terminal 光纤用户线路终端FSM Fast Screen Machine 快速筛选机FSM Field Strength Meter 场强计FSM Fine Striped Memory 细纹存储器，微带存储器FSM Finite State Machine 有限状态机FSM Folded Sideband Modulation 折叠边带调制FSM Forward Set – up Message 前方安装讯息FSM Frequency Shift Modulation 频移调制.fsm Farandoyle的音乐样本文件格式〖后缀〗FSN File Sequence Number 文件序号FSN Forward Sequence Number 正向序号FSN Frequency Subset Number 频率子集编号〖寻呼机〗FSN Full Services Network 全方位服务网络，综合信息网络〖因特网〗FSN Function Service Network 功能服务网络FSO Frequency Sweep Oscillator 扫频振荡器FSP File Services Processing 文件服务处理FSP File Service Protocol 文件服务协议FSP Fleet Scheduling Program 快速调度程序FSP Frequency Shift Pulse 频移脉冲FSP Full – Screen Processing 全屏处理FSP Functional, Security And Performance 功能安全和性能FSPG Fluorescent Security Photo Graphics 荧光防护照片制图FSR Feedback Shift Register 反馈移位寄存器FSR Forward Space Record 正向间隔记录FSR Frequency Shift Receiver 移频接收机FSS First Floor Software 基础软件FSS Fixed Satellite Services 固定卫星业务FSS Fixed Signal Services 固定信号服务FSS Flying Spot Scanner 飞点扫描仪FSS Fragment Free Switching 不分段切换FSS Frames Services 帧服务FSS Full – Screen Scaling 全屏幕缩放FST Facilities Solution Team 设备疑难解答组FST Field STart 字段开始FST File Status Table 文件状态表FST Frequency Shift Transmission 移频传输FST Full STore 存满，存储器满.fst dBFast的可链接程序文件格式〖后缀〗FSTC Finance Service Technology Committee 金融服务技术委员会FSTS Functional Standard Test Specification 功能标准测试规范FSU Facsimile Switching Unit 传真转接器FSU Final Signal Unit 最终信号单元FSVFT Frequency Shift Voice Frequency Telegraph 移频音频电报FSW Frame synchronization Word 帧同步字.fsx Lotus 1-2-3的数据文件格式〖后缀〗FT Fault Tolerance 容错FT Foreign Transaction 外来事务处理FT Fourier Transform 傅里叶变换FT Fractional T1 部分T1线路（提供T1线路部分带宽的数字电话服务）〖视频会议〗FT Frame Transfer 帧传送FT Frederick Terman 弗雷德里克·特曼（硅谷之父）FT Functional Test 功能测试FTA Fast Turn Around 快速周转FTA Fault Tree Analysis 故障树状分析FTA Floptical Technology Association 软盘技术协会FTAM File Telecommunication Access Method 文件远程通信访问方法FTAM File Transfer Access and management 文件传送存取与管理〖国际标准〗FTAM File Transfer And Access Method 文件传送和存取法〖国际标准〗FTAMS File Transfer Access and management Services 文件传送存取和管理服务FTBF Frequency Tuned Bandpass Filter 频率调谐带通滤波器FTC Fast Time Constant 快速时间常数（电路）FTC Fast Time Control 快速时间控制FTC Fault – Tolerant Computer 容错计算机FTC Fault Tolerant Computer 容错计算机FTC Frequency Time Control 频率时间控制FTC Frontier Technologies Corp. 边疆技术公司（美国，出品网络群件）FTC Fuji Telecasting Company Ltd. 富士电视广播公司（日本）FTC The Federal Trade Committee 联邦贸易委员会（美国）FTDS Failure Tolerant Disk Systems 容错磁盘系统FTE Frequency Translation Equipment 频率转换设备FTE Functional Test Equipment 功能测试设备FTF Fast Transversal Filter 快速横向滤波器FTG FighT Game 格斗游戏FTG File Tag Gate register 文件标记门（寄存器）FTI File Tag In register 文件输入标志（寄存器）FTI Fixed Time Interval 固定时间间隔FTL Fast Transient Loader 快速瞬态装入程序FTL Fiber in The Loop 循环光纤FTLAN Fault Tolerant Local Area Network 容错局域网FTM Fiber Termination Module 光纤端接组件FTM File Transfer Manager 文件传送管理器FTM File Transfer Mode 文件传送模式FTM Frequency Time Modulation 频率时间调制.ftm Micrografx的字体文件格式〖后缀〗FTMC Frequency and Time Measurement Counter 频率时间测量计数器FTO File Tag Out register 文件输出标志寄存器FTOP Frequency TOP 最高频率FTP Field Test Procedures 域测试规程FTP (The basic Internet File Transfer Protocol) 因特网基本文件传送协议（网络主机间传送文件的服务协议），档案传送通讯协定（台湾用语）〖因特网〗FTP Foil Twisted – Pair 箔双绞线.ftp FTP Software PC/TCP的配置文件格式〖后缀〗FTPD File Transfer Protocol Daemon 文件传送协议驻留程序〖因特网〗FTPI Flux Transitions Per Inch 磁通转变次数 / 每英寸FTPSVR File Transfer Protocol for Server 服务器文件传送协议FTR Fast Token Ring 快速令牌环FTR File Transfer Requests 文件传送请求FTR Filestore Transfer Routine 文件存储传送例程FTR Full Text Retrieval 全文检索FTR Functional Test Report 功能测试报告FTR Functional Test Request 功能测试请求FTS Fast Track Selector 快速磁道选择器FTS Federal Telecommunication System 联邦远程通信系统（美国）FTS Field Test Support 域测试支持FTS Forward – Transfer Signal 向前传送的信号FTS Frame Transfer System 帧传送系统FTS Free Time System 自由时间系统FTS FutureTech System Inc. 未来技术系统公司（美国，出品笔记本电脑）FTSC Federal Telecommunications Standards Committee 联邦远程通信标准委员会（美国）FTSP Federal Telecommunications Standards Program 联邦远程通信标准计划FTTB Fiber To The Building 光纤到建筑物FTTC Fiber To The Curb 光纤到路边FTTC Fiber To The Customer 光纤到用户FTTH Fiber To The Home 光纤到家FTTO Fiber To The Office 光纤到办公室FTTS Fiber To The Subscriber 光纤到用户FU Fetch Unit 引入单元FU Field Unit 字段单元，信息组单元FU Flight Unlimited 《无限飞行》〖游戏名〗FU Follow – Up 随动FU Functional Unit 功能部件FUA Follow – Up Amplifier 随动放大器FUA frequently used acronyms 常用缩略语〖网语〗Fujitsu 富士通株士会社〖厂标〗FUM Full User Move 用户整体迁移FUN Frye Utilities for Networks 弗赖伊网络实用工具〖软件名〗FUN FUNction 功能，函数，操作FUNI Frame User – to – Network Interface 帧用户到网络接口FUNI Frame – Based User – to Network Interface 基于帧的用户到网络接口FUR Fast Update Request 快速更新请求FV Formula Visualizer 公式可视表述器FV Future Vision 美国“前景”公司（世界著名娱乐光盘制造商）FVC Forward Voice Channel 前推式语音通道FVC Frequency to Voltage Converter 频率－电压转换器FW Fast Write 快写技术〖显卡〗FW Fire Wire “火线”，即IEEE1394（高速外部总线标准）FW FirmWare 固件FW First Word 首字FW Forward Wave 前向波FW Frame Window 框架窗口〖编程〗FW Full Wave 全波.fw FrameWork的数据库文件格式〖后缀〗.fw2 Framework II的数据库文件格式〖后缀〗.fw3 Framework III的数据库文件格式〖后缀〗FWA File Working Area 文件工作区FWA First Word Address 首字地址FWA Fixed Wireless Access 固定无线访问FWA Forward Wave Amplifier 前向波放大器FWA Full – Wave Amplifier 全波放大器FWAC Four Wire Automatic Converter 四线自动转换器FWBA Full – Wave Balanced Amplifier 全波平衡放大器FWCFA Forward Wave Cross Field Amplifier 前向波交叉场放大器FWD Free World Dialup 全球免费拨通，全球免费呼叫FWH Fire Ware Hub 火器集线器〖主板〗FWH Firm Ware Hub 固件集线器，固件中心〖芯片组〗FWHM Full Width at Half Maximum 一半最大值的充足带宽FWIW for what its worth 为其所值〖网语〗FWL Fixed Word Length 固定字长FWM Four – Wave Mixing 四波混合FWR Full – Wave Rectifier 全波整流器FWSE Frequency – Weighted Squared Error 频率加权平方误差FWT Fast Walsh Transform 快速沃尔什变换FWT Fast Wavelet Transform algorithm 快速子波变换算法FWTS Federal Wireless Telecommunications Services 联邦无线远程通信业务.fx FastLynx的在线线导文件格式〖后缀〗FXBIN decimal to FIXed BINary translation 十进制到固定二进制转换FXC Foreign eXchange Circuit 外来交换机线路，国际交换电路.fxd FAXit的电话号码簿文件格式〖后缀〗FXO Foreign eXchange Office 国际交换局.fxp FoxPro的编译文件格式〖后缀〗FXS Foreign eXchange Service 国际交换业务，外汇兑换业务.fxs WinFax的传真传送图形文件格式〖后缀〗FXT Fixed Time Call 定时呼叫FYA for your amusement 供您消遣〖网语〗FYI for your information 仅供参考〖网语〗FYI 福杨主板〖代号〗。
Multiple-edge noise barriers
1 INTRODUCTION The use of a single vertical screen to obstruct the propagation of noise from source to receiver is well known. However, it has been shown’.’ that the use of two or more screens could be considerably more efficient in terms of noise reduction, and construction material. In this paper the principle of using multiple diffracting edges is extended to barriers with a single foundation. Adding side-panels on to a single vertical screen, creating a fork-like profile, is a relatively inexpensive measure, and one which could be applied to barriers already in existence without alteration
Applied Acousrics 44 (1995) 353-367 0 1995 Elsevier Science Limited Printed in Great Britain. All rights reserved 0003-682X195/$9.50 ELSEVIER 0003-682X(94)00032-8
Multiple-Edge Noise Barriers
声弹性螺栓应力测量影响因素
第51卷第2期2020年2月中南大学学报(自然科学版)Journal of Central South University (Science and Technology)V ol.51No.2Feb.2020声弹性螺栓应力测量影响因素韩玉强1，吴付岗1，李明海1，梅军2，王小龙1(1.中国工程物理研究院总体工程研究所，四川绵阳，621900；2.中国工程物理研究院成都科学技术发展中心，四川成都，610200)摘要：为了分析声弹性法螺栓应力测量中的影响因素，从固体质点声弹性理论入手，在模型中加入质点受力形变因素，建立质点时差法应力测量模型；针对螺栓结构建立不同轴向预紧力下应力分布，获得超声传播路径上的应力分布表达式，建立不均匀应力下的螺栓声弹性测量模型；设计应力不均匀区占超声路径比例不同的实验，采用基于ZnO 压电薄膜的方式激发超声，压电薄膜溅射于螺栓表面，避免使用超声耦合层引入的测量误差，得到应力不均匀区与测试误差的关系；进行螺栓反复拉伸后声弹性测量的重复性实验，验证材料性质与螺栓应力测量的关系。
研究结果表明，超声时差与应力呈线性关系；声弹性系数由螺栓的弹性模量、泊松比以及螺栓长度决定；不同应力非均匀区占比的螺栓应力测量误差相同，初始误差小于2%；螺栓反复拉伸后，声弹性螺栓应力测量误差变大；应力分布不会产生测量误差，测量误差来源于材料的非均匀性；经过拉伸后的螺栓，材料中的缺陷和错位增大，增强高频超声的散射，引起应力测量误差变大。
关键词：声弹性；应力分布；压电薄膜；误差中图分类号：TH73文献标志码：A开放科学(资源服务)标识码(OSID)文章编号：1672-7207（2020）02-0359-08Factors influencing measurement of bolt stress based onacoustoelastic effectHAN Yuqiang 1,WU Fugang 1,LI Minghai 1,MEI Jun 2,WANG Xiaolong 1(1.Institute of System Engineering,China Academy of Engineering Physics,Mianyang,621900,China;2.Chengdu Development Center of Science and Technology,China Academy of Engineering Physics,Chengdu,610200,China)Abstract:In order to analyze the influence of various factors on the measurement of bolt stress by acoustoelastic effect,the theory of acoustoelastic of solid particles was analyzed.The stress and deformation factors of particles were introduced into the model and the stress measurement model of particles was established.The stress distributions under different axial preloads was established with the structure of bolt,the stress distribution expression on the ultrasonic propagation path was obtained and the acoustoelastic measurement model of boltDOI:10.11817/j.issn.1672-7207.2020.02.010收稿日期：2019−08−01；修回日期：2019−10−20基金项目(Foundation item)：国家科技重大专项(2019ZX06002021)(Project(2019ZX06002021)supported by the National Scienceand Technology Major Program of the Ministry of Science and Technology of China)通信作者：李明海，博士，研究员，从事装备环境试验和热安全性研究；E-mail:****************第51卷中南大学学报(自然科学版)under uneven stress was established.ZnO piezoelectric film,which was sputtered on the bolt surface,was used to generate ultrasonic and could avoid the measurement error caused by the application of the ultrasonic coupling layer.The relationship between the uneven stress area and the measurement error was obtained.The relationship between the properties of materials and the stress measurement of bolts was verified by the repeated experimentsof acoustoelastic measurement after repeated stretching of bolts.The results show that the ultrasonic time difference is linear with the stress.The acoustoelastic coefficient is determined by the elastic modulus,Poisson's ratio and length of bolt.The error of the different ratios of uneven stress area is the same and the initial error is less than2%.The error of measurement increases after the bolt is repeatedly stretched.The stress distribution can not produce measurement errors while measurement error comes from the non-uniformity of the material.After stretching the bolt,the defects and dislocation in the material increase which may enhance the scatter of high-frequence ultrasonic and amplify the error.Key words:acoustoelastic;stress distribution;piezoelectric film;error螺栓连接强度对系统的可靠性有重要意义。
10种Python聚类算法完整操作示例（建议收藏）
10种Python聚类算法完整操作示例（建议收藏）聚类或聚类分析是无监督学习问题。
它通常被用作数据分析技术，用于发现数据中的有趣模式，例如基于其行为的客户群。
有许多聚类算法可供选择，对于所有情况，没有单一的最佳聚类算法。
相反，最好探索一系列聚类算法以及每种算法的不同配置。
在本教程中，你将发现如何在 python 中安装和使用顶级聚类算法。
完成本教程后，你将知道：•聚类是在输入数据的特征空间中查找自然组的无监督问题。
•对于所有数据集，有许多不同的聚类算法和单一的最佳方法。
•在 scikit-learn 机器学习库的 Python 中如何实现、适配和使用顶级聚类算法。
让我们开始吧。
教程概述本教程分为三部分：1.聚类2.聚类算法3.聚类算法示例•库安装•聚类数据集•亲和力传播•聚合聚类•BIRCH•DBSCAN•K-均值•Mini-Batch K-均值•Mean Shift•OPTICS•光谱聚类•高斯混合模型一.聚类聚类分析，即聚类，是一项无监督的机器学习任务。
它包括自动发现数据中的自然分组。
与监督学习（类似预测建模）不同，聚类算法只解释输入数据，并在特征空间中找到自然组或群集。
聚类技术适用于没有要预测的类，而是将实例划分为自然组的情况。
—源自：《数据挖掘页：实用机器学习工具和技术》2016年。
群集通常是特征空间中的密度区域，其中来自域的示例（观测或数据行）比其他群集更接近群集。
群集可以具有作为样本或点特征空间的中心(质心)，并且可以具有边界或范围。
这些群集可能反映出在从中绘制实例的域中工作的某种机制，这种机制使某些实例彼此具有比它们与其余实例更强的相似性。
—源自：《数据挖掘页：实用机器学习工具和技术》2016年。
聚类可以作为数据分析活动提供帮助，以便了解更多关于问题域的信息，即所谓的模式发现或知识发现。
例如：•该进化树可以被认为是人工聚类分析的结果；•将正常数据与异常值或异常分开可能会被认为是聚类问题；•根据自然行为将集群分开是一个集群问题，称为市场细分。
基于近红外光谱技术的大豆种子老化级别快速鉴别方法研究
基于近红外光谱技术的大豆种子老化级别快速鉴别方法研究时闯杨冬风*吕晨曦（黑龙江八一农垦大学信息与电气工程学院，黑龙江大庆163319）摘要大豆种子容易发生老化并丧失活力，大豆种子活力检测对目前农业生产具有重要意义。
以2020年收获的大豆种子为样本进行人工老化试验，老化时间设置为1、2、3、4、5、6d，以未老化的种子作为对照组，每个老化等级30个样本。
扫描获取全部210条近红外光谱数据，以4∶1的比例划分样本集。
对原始光谱数据建立BP网络模型1，再分别采取多元散射校正和标准正态变量对原始光谱进行预处理，建立模型2、模型3。
比较3种模型可以发现，预处理技术能缩短模型训练时间，同时可以消除部分噪声，提高模型预测能力，且经过标准正态变量处理后的模型结果较优，由于预处理后的数据维度并未发生变化，模型的训练时间较长，不利于实际应用。
因此，采取主成分分析、连续投影法、竞争自适应重加权法对经过标准正态变量处理后的数据进行特征波长变量提取，将光谱数据由原来的1845维降到10维、23维和150维。
对经过特征波长变量提取后的数据分别建立BP网络模型，得到模型4、模型5、模型6。
综合鉴别上述6种模型，其中模型6的分类准确率达到93.43%，训练时间2.25s，说明该模型可以较好地实现对7类不同老化级别的大豆种子快速、无损鉴别。
关键词大豆种子；近红外光谱；活力检测；BP神经网络中图分类号S126；S565.1文献标识码A文章编号1007-5739（2023）21-0126-07DOI：10.3969/j.issn.1007-5739.2023.21.032开放科学（资源服务）标识码（OSID）：Research on Rapid Identification Method of Soybean Seed Aging Grade Based on NearInfrared Spectrum TechnologySHI Chuang YANG Dongfeng*LYU Chenxi(College of Information and Electrical Engineering,Heilongjiang Bayi Agricultural University,Daqing Heilongjiang163319)Abstract Soybean seeds are prone to aging and losing vigor,and soybean seed vigor detection is of great significance to the current agricultural production.Artificial aging experiments were conducted on soybean seeds harvested in2020,with different aging times(1,2,3,4,5,6days),non-aged seeds were used as the control group,and 30samples were set for each aging grade.All210near infrared spectral data were scanned and obtained,and the sample sets were divided by the ratio of4∶1.BP network model1was established for the original spectral data,and then multiplicative scatter correction and standard normal variable were used to preprocess the original spectrum respectively to establish model2and paring the three models,it could be found that preprocessing techniques could shorten the training time of the model,eliminate some noise,and improve the prediction ability of the model at the same time.The model preprocessed by standard normal variable was superior to that preprocessed by the multiplicative scatter correction.Due to the unchanged data dimensions after preprocessing,the training time of the model was longer, which was not conducive to practical application.Therefore,principal component analysis,continuous projection method and competitive adaptive reweighting method were adopted to extract characteristic wavelength variables from the data after standard normal variable,and the spectral data were reduced from the original1845dimension to10,23and基金项目黑龙江省自然科学基金（C2018050）；大庆市科技局科技项目（zd-2019-38）；黑龙江省省属高校基本科研业务费科研项目（ZRCPY201914）。
半监督分类算法代码
半监督分类算法代码半监督学习是一种机器学习范例，其中算法使用大量未标记的数据和少量标记的数据来进行分类。
半监督分类算法的代码可以使用不同的机器学习库来实现，比如Python中常用的scikit-learn 或者TensorFlow等。
下面我将以Python和scikit-learn库为例，简要介绍一个基于半监督分类算法的代码示例。
首先，我们需要导入必要的库和模块：python.import numpy as np.from sklearn.semi_supervised import LabelPropagation.from sklearn.datasets import make_blobs.import matplotlib.pyplot as plt.接下来，我们生成一些模拟数据（这一步在实际应用中可以省略）：python.X, y = make_blobs(n_samples=100, centers=3, random_state=42)。
y[5:]= -1 # 将一部分标签设为未标记。
然后，我们使用LabelPropagation算法进行半监督分类：python.label_prop_model = LabelPropagation()。
label_prop_model.fit(X, y)。
最后，我们可以可视化分类结果：python.predicted_labels = label_prop_model.transduction_。
plt.scatter(X[:, 0], X[:, 1], c=predicted_labels,marker='o', s=50)。
plt.show()。
以上是一个简单的半监督分类算法的代码示例。
在实际应用中，还需要考虑数据预处理、模型调参等步骤。
另外，还有其他的半监督学习算法可以尝试，比如基于图的半监督学习算法等。
希望这个简要的示例能够帮助你理解半监督分类算法的实现过程。
stable diffusion中噪点强度小的表现
stable diffusion中噪点强度小的表现摘要：1.稳定扩散的概述2.稳定扩散中噪点强度的定义3.噪点强度小的表现4.稳定扩散中噪点强度小的影响5.结论正文：一、稳定扩散的概述稳定扩散是指在给定的条件下，粒子在介质中传播的过程。
在这个过程中，粒子受到各种因素的影响，如温度、压力、介质的物理性质等。
这些因素会影响粒子在介质中的传播速度和方向，进而影响到扩散的结果。
二、稳定扩散中噪点强度的定义在稳定扩散过程中，由于受到各种随机因素的影响，粒子的传播路径会产生波动，这种波动被称为噪点。
噪点强度是指这些噪点对粒子传播过程的影响程度。
通常情况下，噪点强度越大，粒子的传播路径波动越大，扩散的结果也越难以预测。
三、噪点强度小的表现在稳定扩散过程中，如果噪点强度较小，那么粒子的传播路径波动也会相对较小。
具体表现在以下几个方面：1.粒子传播的速度和方向变化较小，传播路径相对稳定。
2.粒子在介质中的扩散结果更容易预测，因为波动较小，结果更为稳定。
3.粒子在传播过程中受到的阻力和其它影响因素较小，对粒子的传播影响不大。
四、稳定扩散中噪点强度小的影响在稳定扩散过程中，如果噪点强度较小，会对粒子的传播产生以下影响：1.粒子传播的速度和方向变化较小，使得粒子更容易被控制，从而更容易实现预期的扩散结果。
2.粒子在介质中的扩散结果更容易预测，可以提高扩散过程的效率和准确性。
3.粒子在传播过程中受到的阻力和其它影响因素较小，可以降低粒子在传播过程中的能量损耗，从而有利于粒子传播的远距离传播。
五、结论综上所述，稳定扩散中噪点强度小的表现，有利于粒子传播的稳定性和可控性，可以提高扩散过程的效率和准确性。
Field
Field II仿真超声换能器声场原理昨天开组会⼤家讨论问题，有⼏个疑问被提出来了：1. Field II主要建模算法⽤C代码实现。
2. ⼆维压电陶瓷换能器阵列和CMUT⼆维换能器阵列有什么区别？本⽂只讨论第⼀个问题，第⼆个另⽂细述。
Field II代码和⼤⼆⼩师弟讨论Field II建模CMUT换能器时，发现Field II的Matlab代码只是来做参数配置和调⽤函数的，这些函数编译为可执⾏⽂件，主要的建模算法是⽤C代码实现，⽽这个代码并没有开源。
我给Dr. Jensen发了封邮件要C代码，但愿能回复我。
建模⽅法使⽤空间冲击响应（spatial impulse response）的原理，依托于超声场的线性系统理论。
发射时，当换能器被狄拉克delta函数激发后，空间中每个点的声场是关于时间的函数。
声场可以通过空间冲激响应和激发函数卷积得到。
接收时，把换能器激发函数和发射孔径的空间冲击响应、接受孔径的空间冲击响应卷积得到接收响应，通过换能器的机械电⼦传递函数得到接收电压曲线。
软件使⽤如果只是⽤Field II仿真声场，可以直接调⽤Matlab函数，配置参数，⽐如探头的物理参数（阵元类型，数量，尺⼨，探测物，接收孔径等），然后得到接收信号，可以拿来波束合成。
我们⽤⼀段⽰例程序来产⽣⾎流的接收波束信号如图。
% This examples shows how the procedures can be used for making flow data from a number of scatters in a tube.% Example of use of the new Field II program running under Matlab%% This example shows how flow can simulated%% This script assumes that the field_init procedure has been called%% Example by Joergen Arendt Jensen, March 22, 2011.% Generate the transducer apertures for send and receivef0=3e6; % Transducer center frequency [Hz]fs=100e6; % Sampling frequency [Hz]c=1540; % Speed of sound [m/s]，⼈体内声⾳平均速度lambda=c/f0; % Wavelengthelement_height=5/1000; % Height of element [m]kerf=0.1/1000; % Kerf [m]focus=[0 0 70]/1000; % Fixed focal point [m]% Generate apertureaperture = xdc_linear_array (128, lambda/2, element_height, kerf, 1, 1,focus); % Set the impulse response and excitation of the emit apertureimpulse_response=sin(2*pi*f0*(0:1/fs:2/f0));impulse_response=impulse_response.*hanning(max(size(impulse_response)))'; xdc_impulse (aperture, impulse_response);excitation=sin(2*pi*f0*(0:1/fs:8/f0));xdc_excitation (aperture, excitation);% Set the seed of the random number generatorrandn('seed',sum(100*clock))% Initialize the ranges for the scatterers，⾎管⾥⾯的物质% Notice that the coordinates are in metersx_range=0.015; % x range for the scatterers [m]y_range=0.015; % y range for the scatterers [m]z_range=0.015; % z range for the scatterers [m]z_offset=0.70; % Offset of the mid-point of the scatterers [m]R=0.005; % Radius of blood vessel [m]% Set the number of scatterers. It should be roughly% 10 scatterers per resolution cellc=1540; % Ultrasound propagation velocity [m/s]f0=3e6; % Center frequency of transducer [Hz]lambda=c/f0;N=round(10*x_range/(5*lambda)*y_range/(5*lambda)*z_range/(lambda*2)); disp([num2str(N),' Scatterers'])% Generate the coordinates and amplitude% Coordinates are rectangular within the range.% The amplitude has a Gaussian distribution.x=x_range*(rand(1,N)-0.5);y=y_range*(rand(1,N)-0.5);z=z_range*(rand(1,N)-0.5);% Find which scatterers that lie within the blood vesselr=(y.^2+z.^2).^0.5;within_vessel= (r < R)';% Assign an amplitude and a velocity for each scattererv0=0.5; % Largest velocity of scatterers [m/s]velocity=v0*(1-(r/R).^2).*within_vessel';blood_to_stationary= 0.1; % Ratio between amplitude of blood to stationary tissue amp=randn(N,1).*((1-within_vessel) + within_vessel*blood_to_stationary);% Calculate a suitable Tprftheta=45/180*pi;f_max=2*v0*cos(theta)/c*f0;fprf=3*f_max;Tprf=1/fprf; % Time between pulse emissions [s]Nshoots=128; % Number of shoots% Find the response by calling fieldfor i=1:Nshootsi% Generate the rotated and offset block of samplexnew=x*cos(theta)+z*sin(theta);znew=z*cos(theta)-x*sin(theta) + z_offset;scatterers=[xnew; y; znew;]' ;% Calculate the received response[v, t1]=calc_scat(aperture, aperture, scatterers, amp);% Store the resultimage_data(1:max(size(v)),i)=v;times(i) = t1;% Propagate the scatterers and alias them% to lie within the correct rangex=x + velocity*Tprf;outside_range= (x > x_range/2);x=x - x_range*outside_range;end% Here the display of the data% Here the display of the data is insertedplot(image_data)。
IT专业英语词典-S
safety ground 安全接地samarium 钐sample and hold 采样和保持sample, luminance 亮度取样sample-and-hold amplifier (SHA) 取样及保持放大器sampling 取样sampling converter 取样转换器sampling frequency 取样频率sampling frequency bandwidth 取样频率频宽sampling scope 取样显示器sampling theorem 采样定理，抽样定理sampling, equivalent time 等效时间取样sampling, simultaneous (SS) 同时取样sandbox model 砂箱模型sandbox security 砂箱安全saponifier 皂化剂；皂化器satellite 卫星satellite communications 卫星通信satellite master antenna television (SMATV) 卫星控制天线电视satellite transmission 卫星转播satellite, direct broadcast (DBS) 直接转播卫星saturated effect 饱和效应saturated vapor 饱和蒸汽saturated vapor pressure 饱和汽压saturation condition 饱和状态saturation flux density 助剂饱和密度saturation line 饱和曲线saturation point 饱和点saturation region 饱和区saturation value 饱和值saturation, magnetic 磁饱和saturation, quasi- 虚饱和saver, power 省电器scalability 伸缩性scalable 可定标scalable architecture 可定标结构scalable coherent interface (SCI) 可定标连贯接口scalar 标量scalar product 标积scalar quantity 标量scalar, pre- 预标定器scale 刻度；标度scale, Celsius 摄氏温标scale, Fahrenheit 华氏温度计scale, Kelvin 开氏温标scale, absolute temperature 绝对温标scale, angular 角度盘scale, diatonic 自然音阶scale, equally tempered 同特征标度scale, full 全标度scale, gray 灰度scale, horizontal 水平标度scale, major diatonic 大自然音阶scale, musical 音阶scale, temperature 温差scale, vertical 垂直标度scaler 定标器scan 扫描scan path 扫描路径scan rate 扫描率scan, boundary 边缘扫描scan, double 双扫描scan, helical 螺旋式扫描scan, raster 光栅扫描scanner 扫描器scanner, bar code 条码扫描器scanner, image 影像扫描器scanning 扫描scanning acoustic microscope 扫描声学显微镜scanning electron microscope 扫描式电子显微镜scanning frequency 扫描频率scanning line 扫描线scanning tunneling microscope (STM) 扫描隧道显微镜scanning, arc 弧形扫描scanning, horizontal 水平扫描scanning, interlaced 交织扫描；隔行扫描scanning, sequential 逐行扫描；顺序扫描scanning, vertical 垂直扫描scatter propagation 散射传播scattered light 散射光scattering 散射scattering, back- 反向散射scattering, total 总散射scatternet 分布网，分散网，散射网scavenge pad 清洗焊盘，清洗焊接点scheduler 调度程序schemata 图解schematic 原理图schematic capture 原理图攫取scheme 电路；模式scheme, arbitration 判优电路scheme, register bank 寄存器组电路science, cognitive 认知科学scope 范围scope, sampling 取样示波器scoreboarding 寄存器记数scrambler circuit 密码转换器电路scrambling 加扰scrap 报废；废料screen 屏幕screen printer 丝网印刷机；网印机screen printing 丝网印刷screen, anti-glare 不反光屏幕screen, fluorescent 萤光幕screen, focusing 对焦屏screen, solar projection 太阳投射屏幕screen, touch 触按式屏幕screen, touch control 触按式屏幕scribe and break 划线及折断scripting language 描述语言，[UNIX]过程语言scroll 卷页sea of gates 门海sea-of-cells 海量单元sea-of-gates 海量门数seamless 无接口search engine 搜索引擎search, binary 二元搜寻search, binary tree 二元树状搜寻search, comparative 比较式搜寻search, distributive 分配式搜寻search, external 外部搜寻search, internal 内部搜寻search, linear 线性搜寻search, sequential 顺序搜寻searching 搜寻secant 正割second 秒second source 第二源second, byte-per- 每秒字节数second, character-per- (CPS) 每秒字数second, cycle-per- (CPS) 每秒周期数second, micro- 微秒second, milli- (ms) 毫秒second, million floating point operations per (MFLOPS) 每秒百万次浮点运算second, million instruction bytes per (MIBS) 每秒百万指令字节second, million instructions per (MIPS) 每秒百万条指令second, million samples per 每秒百万次取样second, nano- (ns) 毫微秒second, pico- (ps) 微微秒second-level cache (L2) 次级高速缓冲存储器secondary 次级；辅助secondary battery 次级电池secondary breakdown 次级击穿secondary coil 次级线圈secondary current 次级电流secondary data structure 次级数据结构secondary ion mass spectrometry (SIMS) 二次离子质谱测定法secondary output 二次输出；次级输出secondary storage 次级储存secondary voltage 次级电压section 区段section offset 区段偏移section overhead (SOH) 段过载，段开销section, cross- 截面section, principal 主截面sectionalizer 分段器sector 磁区sector antenna 扇面天线sector index 磁区索引sector, boot 启动磁区secure hash algorithm (SHA) 安全散列算法secure hypertext transfer protocol (SHTTP) 安全超文本传送协议secure multimedia Internet mail extension (S/MIME) 安全多媒体因特网邮件扩展secured electronic transaction (SET) 安全电子交易security management 安全性管理sedimentation 沉积seed value 晶粒值，晶种数量seek time 寻找时间seesaw switch 反相式开关segment 分段segment address 分段地址segment handling 分段处理segment handling interrupt 分段处理中断segment offset 分段偏移segment register 分段寄存器segment, code 代码分段segment, local 本部分段segment, paging 分页分段segmentation 分段segmentation and reassembly (SAR) 拆分和组装segmentation, memory 存储器分段seismic wave 地震波selected area chemical vapor deposition (SACVD) 区域可选化学汽相淀积，选定区域化学蒸发沉积[法]selection sort 选择式排序selective area laser deposition (SALD) 选择区域激光沉积selective laser sintering (SLS) 选择性激光烧结，选区激光烧结selective reflection 选择反射selector 选择器selenium (Se) 硒self discharge 自放电self healing network 自愈网self-alignment 自对准，自定位self-diagnostics 自我诊断self-healing network 自愈网络self-inductance 自感self-phase modulation (SPM) 自相位调制self-resonant frequency (SRF) 自谐振频率self-solder quad flat pack (SSQFP) 自焊接式四方扁平封装semantic content 语意内容semaphore 信号semi-aqueous cleaning 半水洗semi-custom 半定制semi-customize 半定制semiaqueous cleaning 半水洗semiconductor 半导体semiconductor manufacturing technology research consortium (SEMATECH) 半导体制造技术研究联盟semiconductor, N-channel metal oxide (NMOS) N 通道金属氧化半导体semiconductor, N-type N 型半导体semiconductor, P-channel metal oxide (PMOS) P 通道金属氧化半导体semiconductor, P-type P 型半导体semiconductor, bipolar complementary metal oxide(BiCMOS) 双极互补金属氧化半导体semiconductor, bipolar metal oxide (BiMOS) 双极金属氧化半导体semiconductor, complementary metal oxide (CMOS) 互补金属氧化半导体semiconductor, dielectric isolated complementary metal oxide (DICMOS) 介电质隔离互补金属氧化半导体semiconductor, metal oxide (MOS) 金属氧化半导体send 发送sending mode 发送模式sensing, remote 遥感sensitive, edge 边缘敏感sensitive, level- 电平敏感sensitivity, light 光敏度sensor 传感器sensor, humidity 湿度感应器sensor, image 影像感应器sensor, photo 光感应器sensor, thermocouple 热偶感应器separate audio program (SAP) 音频分离节目，音频独立节目separation 分隔；分离separator 分隔字符；分隔器separator, data 数据分隔器separator, encoder/decoder data 编码器／解码器数据分隔器sequence 序列sequence function chart (SFC) 序列函数图；序列功能图sequence number 序号，顺序号，流水号sequence, data 数据序列sequence, frame check (FCS) 信息段检测序列sequence, instruction 指令序列sequence, pseudo-random 虚随机序列sequencer 定序器sequencer, programmable (PROSE) 可编程定序器sequencer, timing 时序定序器sequencer, trigger 触发定序器sequential 序列的；顺序的sequential access 序列存取；顺序存取sequential build-up 顺序内建sequential chain 序列链路sequential construct 序列构造sequential list 顺序列sequential mapping 顺序映射sequential packet exchange (SPX) 顺序分组交换sequential process 序列处理sequential scanning 逐行扫描；顺序扫描sequential search 顺序搜寻sequential system 序列式系统sequential transfer 顺序传输sequential transmission 顺序传输sequential trigger 序列触发sequential-repetitive 顺序重复serial 串行serial adapter 串行配接器serial bit 串行位serial byte 串行字节serial communication controller (SCC) 串行通讯控制器serial communications 串行通讯serial compiler 串行编译器serial controller 串行控制器serial copy management system (SCMS) 串行拷贝管理系统serial data in (SDI) 串行数据输入serial data out (SDO) 串行数据输出serial interface 串行接口serial interface engine (SIE) 串行接口引擎serial line Internet protocol 串行线路Internet协议serial line internet protocol (SLIP) 串行线路接口协议serial peripheral interface (SPI) 串行外设接口serial port 串行端口serial pulse-code modulation interface 串行脉冲编码调制接口serial read port 串行读取端口serial register 串行寄存器serial transmission 串行传输serial, word 字串行serial-in parallel-out (SIPO) 串入并出serial-in serial-out (SISO) 串入串出serialize 串行化serializer 串行器serializer shift clock 串行器变换时钟series 序列；系列；串联；串行series combination 串联汇编series gating 串连门series spectrum 系线谱server 服务器server, communication 通讯服务器server, disk 磁盘服务器server, file 文件服务器server, network 网络服务器service access point (SAP) 业务接入点；服务访问点service access point identifier (SAPI) 服务存取端识别码service access protocol (SAP) 业务接入协议service advertising protocol (SAP) 业务广告协议service control function (SCF) 业务控制功能service control point (SCP) 业务控制点service creation environment (SCE) 业务创新环境service creation environment function (SCEF) 业务创新环境功能service data function (SDF) 业务数据功能,服务数据功能service data point (SDP) 业务数据点service data unit (SDU) 服务数据单元service ids/sids 多重服务识别代码service lateral 服务支线service level agreement (SLA) 服务级协议service level agreement/slas 服务级协议service location protocol (SLP) 业务定位协议service logic program 业务逻辑程序service management function (SMF) 业务管理功能service management system (SMS) 业务管理系统service node (SN) 业务节点service point 服务点service switching function (SSF) 业务交换功能service switching point (SSP) 业务交换点service, advanced communications (ACS) 先进通讯服务service, bulletin board (BBS) 电子布告板服务service, dataphone digital (DDS) 数据电话机数字服务service, quality of (QOS) 服务品质service, remote file (RFS) 远程文件服务service, wide area telecommunications (WATS) 宽域性远程通讯服务service-specific convergence sublayer (SSCS) 特定业务汇聚子层services switching point (SSP) 业务交换点services, basic communications 基本通讯服务serving GPRS support node (SGSN) GPRS业务支撑点serving office (SO) 服务处，维修处servo 伺服servo burst 伺服脉冲servo controller 伺服控制器servo demodulator 伺服解调器servo motor 伺服马达servo profile 伺服描述servo signal 伺服信号servo, continuous composite (CCS) 连续合成伺服servowriting 伺服写入session 对话session initiation protocol (SIP) 话路启动协议session layer 对话层set 集set instruction 指令集set, character 字符集set, multi-register (MRS) 多重寄存器集set, register 寄存器集set, virtual command 虚拟命令集set-point 设定值，给定值；调整点set-top box 机顶盒set-top cable boxes 有线电视机顶盒setting time 建立时间，稳定时间，置位时间setting, aperture 光圈调校setting, default 缺省设定setup 装设severely errored second (SES) 严格误差秒,严重误差秒shade 色调；阴影；浓淡shadow 阴影shadow photometer 阴影光度计shadow random access memory 阴影随机存取存储器shadowing 遮蔽；加阴影；变暗shaft 传动轴；轮轴shallow discharge 表面放电shallow trench isolation (STI) 浅沟道隔离[技术]shape deposition manufacturing (SDM) 形态沉积制造shape deposition modeling (SDM) 形态沉积建模shared library 分享程序库shared memory 分享存储器shared memory protocol 分享存储器协定shared wireless access protocol (SWAP) 共享无线接入协议shared-resource 分享资源shareware 共享件sharing, time 分时shear 切力shear force 切力shear modulus 切变模量shear strength 剪切强度sheath 护套sheath miles of fiber 光纤护套里数sheet 薄层sheet dielectric 片状介电质sheet resistance 表面电阻；薄层电阻sheet, mica 云母片shelf life 保存期限，储存寿命shell 壳体shell driven 壳体驱动shell-driven interface 壳体驱动接口shield 屏蔽；掩蔽shielded inductor 隔离电感器shielded twisted pair (STP) 屏蔽双绞线对shielded wire 屏蔽线；隔离线shielding 屏蔽shielding, magnetic 磁屏shift clock 变换时钟shift key 字母变换键shift lock key 字母变换锁定键shift rate 位移率shift register 位移寄存器shift, bit 位移位shift, level 电平位移shift, phase 相位位移；相位转移shift, under-phase- 下相位位移shifter 位移器shifter, barrel 柱式位移器shifter, length 长度位移器shifter, level 电平位移器shifter, logic-level 逻辑水平位移器shipper 船务公司shipping tube 输送管道,航运通道shock wave 冲击波shock, thermal 热击shooter, chip 片式元件组装机shop floor line management (SFLM) 商店地面走线管理short 短路short circuit 短路short dipole 短偶极天线，短偶极振子，短偶极子short message service (SMS) 短报文业务short wave 短波short-circuit protection 短路保护short-reach 短到达shrink quad flat package (SQFP) 缩小四方扁平封装shrink small-outline package (SSOP) 缩小外型封装shrinkable tube 热缩管shunt 分流；分流器；旁路shunt capacitance 分流电容shunt circuit 分流电路shunt compensation 分流补偿；旁路补偿；旁路电阻shunt loss 分流损耗shunt regulation 分流调节，并联调节shunt resistance 分流电阻；旁路电阻shunt transistor 分流晶体管shunted condenser 旁路电容器shutdown 停机shutter 快门shutter speed 快门速度side band 频带side, component 元件板面side, solder 焊接板面sideband 边带sideband signaling 边带信令sidetone 侧音调sign convention 符号规约sign up 签约雇用signal 信号signal attenuation 信号衰减signal circuitry 信号电路signal computing system architecture (SCSA) 信号计算系统结构signal dispersion 信号散射，信号弥散现象signal fade margin 信号衰落储备，信号衰落界限signal fidelity 信号保真度signal generator 信号产生器signal ground 信号地signal integrity 信号完整性,信号完备性signal integrity analysis 信号完整性分析,信号完备性分析signal inversion 信号逆转signal processing 信号处理signal quality error SQE 信号质量错误signal state diagram 信号状态图signal timing 信号时序,信号定时signal, acknowledge 收完成信号signal, baseband 频带信号signal, color difference 彩色区分信号signal, common clock 共同时钟信号signal, common-mode 共态信号signal, cross 信号交接；信号交越signal, down-converted 下转换信号signal, reset 重设信号signal, servo 伺服信号signal, spurious 寄生信号signal, status 状态信号signal, strobe 选通信号signal, time-sampled 时间取样信号signal, video 视频信号signal-level meter (SLM) 信号电平计signal-to-noise ratio (SNR) 信噪比signal-to-quantization noise ratio (SQNR) 信号-量子化噪音比signaling 信令；发信号，发码signaling connection control part (SCCP) 信令连接控制部分signaling data link (SDL) 信令数据链路signaling data link functions (SDL) 信令数据链路功能signaling end point (SEP) 信令端点signaling link functions 综合链路功能signaling message handling 信令消息处理signaling network functions 信令网功能signaling network management 信令网管理signaling point (SP) 信令点signaling transfer and end point (STEP) 信令传送和端点signaling transfer point (STP) 信令转发点signaling, common channel (CCS) 公共通道信号传送signaling, functional 功能式发信signaling, out-of-band 频带外传信signaling, stimulus 激发性发信signaling, system 信令系统signature 标记图；辨认记号signature analysis 署名特征分析significant bit 有效位significant figure 有效数字silence suppression 静音抑制silicide 硅化物silicon (Si) 硅silicon dioxide 二氧化硅silicon nitride 氮化硅silicon real estate 硅片空间silicon wafer 硅晶圆silicon, local oxidation of (LOCOS) 区域性硅片氧化silicon-controlled rectifier (SCR) 硅控整流器silicon-dioxide layer 二氧化硅层silicon-on-insulator (SOI) 绝缘体上硅芯片siliconization 硅片化silkscreen 丝网simple distributed security infrastructure (SDSI) 简单分布式安全基础结构simple harmonic motion 简谐运动simple mail transfer protocol (SMTP) 简单邮件传输协议simple matrix 简单矩阵simple matrix display 简单矩阵显示simple network management protocol (SNMP) 简单网络管理协议simple network management protocol version 2 (SNMPv2) 简单网络管理协议版本2simple network time protocol (SNTP) 简单网络时间协议simple public key infrastructure (SPKI) 简单公共密钥基础结构simple workflow access protocol (SWAP) 简单流程接入协议simplex 单工simplex transmission 单工传输，单向传输simulate 模拟simulated performance with integrated circuit emphasis(SPICE) 以集成电路效能为重心的模拟表现simulation 模拟simulation board design (SBD) 仿真板设计simulation pattern 模拟模式simulation program with integrated circuit emphasis(SPICE) 以集成电路为重心的模拟程序simulation vector 模拟向量simulation, behavioral 性能模拟simulation, device 器件模拟simulation, fault 故障模拟；错误模拟simulation, functional 功能模拟simulation, interconnection 互连模拟simulation, realtime 实时模拟simulation, transient linear 瞬变线性模拟simulator 模拟器simulator, functional 功能模拟器simulator, harmonic balance 谐波平衡模拟器simulator, post-layout 后布置模拟器simulcast 同时联播simultaneous sampling (SS) 同时取样simultaneously switching noise 并发开关噪声sine 正弦sine wave 正弦波sine-wave generator 正弦波产生器single channel per carrier (SCPC) 单边带载波single crystalline 单晶体single crystalline layer 单晶体层single crystalline silicon layer 单晶硅层single density (SD) 单密度single instruction/multiple data (SIMD) 单指令／多重数据single layer TAB tape 单层TAB带single layer ceramic (SLC) 单层陶瓷single mode fiber 单模光纤single phase 单相／单相位single phase line 单相线路，单相输电线路single precision 单精度single side band noise 单面频带噪声single sideband 单边带single sided board 单面频带single-attached connection 单配附连接single-attached station (SAS) 单配附传讯站single-chip microcomputer (SCM) 单芯片微电脑single-cycle address translation 单周期循环地址转换single-in-line memory module (SIMM) 单列存储器模组single-in-line package (SIP) 单列直插式封装single-layer board 单层板single-layer metal (SLM) 单层金属single-line DSL (SDSL) 单线DSL,单线数字用户线single-mode fiber 单模光纤single-sideband noise 单面频带噪声single-sided board 单面电路板single-tone desensitization 单音灵敏度下降sinking current 吸收电流site 地址，场所，现场skew 歪曲率skew, time 时滞skid control 滑动控制，刹车控制skin effect 趋肤效应，集肤效应sky wave propagation 天波传播slave 从属；从属器sleep mode 休止模式slew rate (SR) 转换率slice 截割slice, bit 位截割slice, cache 高速缓冲存储器截割slice, time 分时slicer 截割电路；截割器slide carrier 幻灯片托架slide switch 滑动式开关slider 滑杆sliding friction 滑动摩擦sliding window protocol 滑动窗口协议slip 电报纸条；滑动，滑步slip connection 滑动连接slope 斜率slope overload 斜率过载slope, bias 偏移斜率slot 间隙；磁格；槽口slot antenna 槽形天线，隙缝天线slot connector 槽连接器slot, expansion 扩展槽slot, time 时序间隙slump, solder mask 焊锡掩膜下陷small computer system interface (SCSI) 小型电脑系统接口small loop antenna 小环形天线small office and home office (SOHO) 小型及家庭办公small-outline J-lead package (SOJ) 小外型J 接脚封装small-outline integrated circuit (SOIC) 小外型集成电路small-outline package (SOP) 小外型封装small-outline transistor (SOT) 小外型晶体管small-scale integrated circuit (SSIC) 小规模集成电路small-scale integration (SSI) 小规模集成smart card 灵巧卡smart modem 灵巧型调制解调器smart phone 智能电话smart power 灵巧化功率smart sensor 智能传感器snooping 窥探snooping, bus 总线窥探snooping, cache 高速缓冲存储器窥探snubber 缓冲器，消声器，减振器soak zone 均热处理器society of cable television engineers (SCTE) 有线电视工程师学会socket 插座socket, test 测试用插座sodium (Na) 钠sodium cyanide 氰化钠sodium lamp 钠弧灯soft ACD 软件ACDsoft adjacent layer (SAL) 软相邻层soft error 可更正错误；软错误soft handover 软件切换; 软件移交soft key 软键soft logic 软逻辑soft permanent virtual circuit (SPVC) 软永久虚电路soft permanent virtual path connection (SPVPC) 软永久虚路径连接soft start 软启动soft start circuit 软启动电路soft state 软状态software 软件software algorithm 软件演算法software driver 软件驱动程序software fault isolation (SFI) 软件故障隔离，软件错误隔离software library 软件库software modem 软件调制解调器software package 套装软件software portability 软件可移植性software repository 软件存储库software reusability 软件可复用性software tool 软件工具software trigger 软件触发software, navigation 导引软件；导航软件software, presentation 简报软件software, public domain 公用软件software-transparent 软件透明software-transparent cache 软件透明高速缓冲存储器solar battery 太阳电池solar cell 太阳能电池solar energy 太阳能solar projection screen 太阳投射屏幕solder 焊接solder ball 焊锡球solder bath 焊浴solder bead 焊珠solder bridge 焊桥solder bump 撞击焊；焊接凸点solder connection 焊料连接solder flow 焊锡流solder junction 焊接点solder leveling 焊料匀称solder mask 阻焊剂；焊锡掩膜；绿漆solder mask over bare copper (SMOBC) 裸铜阻焊剂，铜箔阻焊膜solder paste 焊膏；锡膏solder powder 焊料粉末solder side 焊接板面solder spatter 焊料飞溅solder spike 焊料毛刺solder wicking 焊芯solder-mask slump 焊锡掩膜下陷solderability 可焊性；可焊度soldering technique 焊接技巧soldering time 焊接时间soldering, double-wave 双波峰焊接soldering, high-temperature 高温焊接soldering, no-clean 免清洗焊接soldering, reflow 回流焊接soldering, vapor-phase reflow 汽相回流焊接soldering, wave 波峰焊接soldering, zero defect 零缺点焊接solenoid 螺线管solid 固体solid angle 立体角solid-oxide fuel cell (SOFC) 固体氧化物燃料电池solid-state 固态solid-state laser 固体激光器solid-state physics 固态物理学solid-state relay (SSR) 固态继电器solidification 凝固solidification, heat of 凝固热solidifying point 凝固点soliton 孤子，光孤子solubility 溶度solution, aqueous 水溶剂solvent 溶剂solvent extraction 溶剂萃取；溶剂抽取sonar 声纳sonobuoy 声纳浮标sonometer 听力计；弦音计sort, bubble 气泡排序sort, comparative 比较式排序sort, distributive 分配式排序sort, external 外部排序sort, insertion 插入式排序sort, interchange 交换式排序sort, internal 内部排序sort, merge 合并式排序sort, partition exchange 划分交换式排序sort, quick 快速排序sort, selection 选择式排序sorting 排序sound 声sound spectrum 声谱sound speed 声速sound track 声迹sound wave 声波source 源source code 源代码source coherent, 相干源source file 源文件source interrupt 中断源source operand 源运算元source program 源程序source route bridging 源路由桥接source routing 源路由选择，源选路source voltage effect 源电压效应source, light 光源source, line- 线发射源source, point 点光源source, potential 电位源；电势源source, second 第二源source-code debugger 源代码除错程序source-level portability 源水平可移接性source-measure unit (SMU) 源量度单元source/drain extension (SDE) 源/漏极外延，源/漏极扩展sources, coherent 相干源space 空间，间隔，间距，留空白space charge 空间电荷space diversity 空间分集space division switching 空分交换space network 空间网络space potential 空间电位space wave propagation 空间波传播space, Faraday dark 法拉第暗区space, cathode dark 阴极黑暗区space-division multiple access (SDMA) 空分多址接入，空分多路存取space-time coded modulation (STCM) 空-时编码调制space-time-space switching (STS) 空-时-空交换,空-时-空交换网络spacing 空间；距离；间距spacing ratio (SR) 空间比；间隔比spacing, probe 探针距离spanning tree algorithm 生成树算法spark 火花spark-gap capacitor 放电电容器spatial attenuation 空间衰减spawning 大量生成,衍生spawning networks 衍生网络speaker 扬声器speaker-dependent recognition 与口音相关的语音识别speaker-independent recognition 与说话者无关的语音识别，与口音无关的语音识别speakerphone 免提听筒电话special function register (SFR) 特殊功能寄存器specialized mobile radio (SMR) 专用移动无线电specialized resource function (SRF) 专业化资源用途，专用资源功能specialty memory 专用存储器specific gravity 比重specific heat at constant pressure 定压比热specific heat at constant volume 定容比热specific heat capacity 比热容specific ionization 电离比值specific latent heat 比潜热specification 规格specification and description language (SDL) 规范和描述语言specification, enhanced expanded memory (EEMS) 增强扩充存储器规格specification, expanded memory (EMS) 扩充存储器规格specification, extended memory (XMS) 延伸存储器规格specification, initial graphic exchange 初始图像交换规格spectral analysis 频谱分析spectral bandpass 频谱带通，光谱带通spectral efficiency 频谱效率spectral line 光谱线spectral shaping 频谱定形spectrogram 光谱图spectrometer 分光仪；光谱仪；能谱仪spectrometer, X-ray X 射线光谱仪spectrophotometer 分光光度计spectrophotometry 分光光度学spectroscope 分光镜spectroscopy 光谱学spectrum 光谱；频谱spectrum analysis 光谱分析spectrum analyzer 频谱分析仪spectrum filtering 光谱过滤spectrum, X-ray X 射线谱spectrum, absorption 吸收光谱spectrum, band 频带光谱spectrum, continuous 连续谱spectrum, dark line 暗线光谱spectrum, electromagnetic 电磁波谱spectrum, emission 放射光谱spectrum, impure 不纯粹光谱spectrum, mass 质谱spectrum, optical 光谱spectrum, pure 纯粹光谱spectrum, series 系线谱spectrum, sound 声谱spectrum, visible 可见光谱specular reflection 镜面反射speech digit signaling 语音数字信令speech integrated circuit 语音集成电路speech network 语音网络speech path 语音通路speech recognition 语音识别speech synthesizer 语音合成器speech-actuated manipulator 声控操纵器,语音激励发报机speed 速度speed dialing 快速拨号speed, shutter 快门速度speed, sound 声速speed, uniform 均速speedometer 速度计spherical aberration 球面像差spherical mirror 球面镜spherical wave 球面波spike 尖峰；尖峰信号spin 旋转spin glass 旋转镜片spin motor 旋转马达spindle bearing 转轴轴承spiral inductors 螺旋电感splice 接头，叠接，绞接splice closure 接头盒，接头套管splice tray 粘贴槽，接合盘splicing 拼接;粘贴splitter 分离器splitter, beam 分光镜spoke type 辐条式spontaneous emission 自发放射spoofing 电子欺骗spooking 鬼影spooling 假脱机[打印]spot size 光点spot, blind 盲点spot, hot 过热点spread 伸展，扩展;发散spread spectrum 扩展频谱spreader, heat 散热器spreading code 扩展代码spreadsheet 试算表spring force 弹压力spring, hair 游丝sprite 浮标sprite controller 浮标控制器sprocket holes 中导孔，输送孔，定位孔sprocket pitch 链轮齿距spurious free dynamic range (SFDR) 无寄生动态范围；纯动态范围spurious phase modulation (SPM) 寄生调相，乱真调相spurious response 寄生反应spurious signal 寄生信号sputter etch process 溅镀蚀刻过程sputtering 溅镀sputtering, ion 离子溅镀square grid 方栅square wave 方形波square, least-mean- (LMS) 最小均方square, root-mean- (RMS) 均方根square, true root-mean- (TRMS) 真实均方根squeegee 印刷刮板，印刷刮刀squeegee stroke 刮板印刷行程ssinging 振鸣，啸声stability 稳定性stability, high-temperature 高温稳定性stability, thermal 热稳定性stabilizing power 稳压电源stable equilibrium 稳定平衡stack 堆栈stack register 暂存堆栈器stack, circular 环形堆栈stack, hardware 硬件堆栈stack, rack-and- 机架汇编式-vacuum architecture分段式真空结构stacked chip-scale package 堆栈式CSP封装，叠式CSP封装standalone ACD 独立的自动呼叫分配standard Ethernet cable 标准以太网电缆standard MIB 标准管理信息库standard MIDI file (SMF) 标准的MIDI文件standard atmospheric pressure 标准大气压力standard candle 标准烛光standard cell 标准电池；标准储存格standard condition 标准状况standard definition TV (SDTV) 标准清晰度电视standard definition television 标准清晰度电视standard deviation 标准偏差standard discrete logic 标准离散逻辑元件standard error 标准误差standard exponential atmosphere 标准指数大气压，标准指数大气层standard linear atmosphere 标准线性大气压standard positioning service (SPS) 标准定位业务standard resistor 标准电阻standard test interface language (STIL) 标准测试接口语言standard unit 标准单位standard, data encryption 数据加密标准standard, de facto 约定俗成的标准standards bodies 标准体，标准机盒standby current 待机电流standby mode 候命状态；预备状态standby network link group 备用网络链路组standing wave 驻波standoff 隔开；支座；远离star connection 星形连接star coupler 星形偶合器star network 星形网络star network topology 星形网络拓扑start bit 起始位start-up circuitry 起动电路start-up delay 启动延时start-up sequence 启动顺序start/stop transmission 起止式传输state 状态state data 状态数据state detection 状态检测state diagram 状态图state list 状态表列state logic 状态逻辑state machine 状态机器state one wait, 一个等候状态state zero-wait, 零等候状态state, crystalline 晶态state, excited 受激状态state, gaseous 气态state, ground 基态state, initial 初始状态state, logic 逻辑状态state, steady- 稳定状态state, wait 等候状态state-average model 状态平均模型state-machine compiler 状态机器编译程序statement 述句；陈述statement, conditional 条件式述句statement, trace 追迹陈述statfarad 静电法拉static 静态static burn-in 静态老化测试static charge 静电荷static control system 静电防护系统static dissipative material 静态损耗材料static electricity 静电static flex 静态弯曲static friction 静摩擦static load 静态负载static magnetic field 稳恒磁场static random access memory (SRAM) 静态随机存取存储器static scanning 静态扫描static structural analysis 静态结构分析static uninterruptable power supply 静态式不断电源供应static, pseudo- 虚静态static-column page-mode memory 静态纵列分页模式存储器static-safe area 静电安全区static-sensitive device 静电敏感元件statics 静力学station 站，台，局；用户话机；用户设备；用户点station management (SMT) 站管理station message detail recording (SMDR) 站报文详细记录,用户通话详细记录，详细话单station, base 基站station, dual-attached (DAS) 双配附传讯站station, network 网络站station, single-attached (SAS) 单配附传讯站stationary wave 驻波statistical analysis 统计分析statistical multiplexing 统计多工statistical physics 统计物理学statistical process control (SPC) 统计式过程控制statistical quality control (SQC) 统计式品质控制status 状态status bit 状态位status byte 状态字节status information 状态信息status signal 状态信号steady flow 稳流steady state 稳定状态stencil 模板，漏印板stencil printing 模版印刷stencil wiping [ 漏印]模版擦拭step change 步长变化，节距变化step control 步进控制step motor 步进马达step-Index multimode fiber 阶跃折射率多模光纤step-down ratio 降压比率step-down transformer 降压变压器step-index monomode fiber 阶跃折射率单模光纤step-up ratio 升压比率step-up transformer 升压变压器stepper motor 步进电机stereo graphic equalizer 立体声图形均衡器stereolithography 立体平版印刷stiction 黏滞still-video camera 静止视频照相机stimulated emission 受激发射stimuli, test 测试刺激stimulus pattern 刺激模式。
Negative concentrations(comsol中负浓度的处理方法)
Results With Small Unphysical ValuesWHERE AND WHY DO UNPHYSICAL VALUES APPEAR?In some models small unphysical values can occur due to numerical artifacts. Examples include: •Negativeconcentrations in mass transfer . •A temperature that is slightly higher than the initial condition in time dependent heat transfer studies. •Small reaction forces that appear in unloaded directions in structural mechanics models. •Small negative gaps in a contact analysis. •Small negative effective plastic strain values. •Stresses above the yield limit for an ideally plastic material in solid mechanics. Some reasons for why these unphysical values occur:•Numerical noise is a common cause. When the values of the dependent variables approach zero, the numerical noise can become relatively significant and cause some of the results to be slightly negative even if that is not physically possible. •Interpolation and extrapolation of values can cause some values to become unphysical. For example, results for an elastoplastic material are correct (within some tolerance) at the integration points (Gauss points) inside the finite elements, but values might become unphysical when extrapolating the data to the element boundaries. •Discontinuities in the model is another source of, for example, small negativeconcentrations due to a discontinuous initial value. With an initial value that is zero along a boundary for a convective transport models, for example, the physical interpretation is an initially sharp, gradually diffusing front moving away from the boundary. However , for the default shape function (second-order Lagrange elements), only continuous functions are admissible as solutions for the finite element model. The program then modifies the discontinuous initial value before the time stepping can begin. This often results in a small dip in the solution at the start time. In the example model that the following figure shows, the concentration is locally slightly negative at t = 0: • Lack of mesh resolution is another cause of unphysical values such as negativeconcentrations. The resulting convergence problems are often the underlying issue when negativeconcentrations are observed in high convection regimes (high Peclet number) and in those with large reaction terms or fast kinetics (high Damkohler number). •Incorrect physics in the model can also cause these types of problems. For mass transfer , for example, the use of a constant sink in a reaction term is an approximation that only works for large concentrations. When the concentration reaches zero, the reaction term continues to consume thespecies, finally resulting in a negative concentration. AVOIDING UNPHYSICAL VALUESThis section contains some ways to avoid computing or displaying unphysical values:•In some cases it is possible to add a baseline to the dependent variable so that the numerical noise does not affect the solution in the same way as when the values of the dependent variable approach zero. This scaling is not possible with, for example, a reaction term that depends on the concentration because then the scale and origin do matter . •Avoid discontinuities in the model by using, for example, the available smoothed step functions instead. •Formulate logarithmic variables as a way of eliminating mesh resolution problems and negative dips by using the logarithm of the original dependent variable (the concentration, for example) as the dependent variable. The reason for this is that a linearly varying mesh can sometimes not capture the exponential behavior of the changes in the dependent variable. In addition, modeling the logarithm of the dependent variable ensures that the real concentration, for example, cannot become negative during the solution process. •Avoid displaying small unphysical values due to numerical noise by clipping the values for the plot. You can do this by plotting, for example, c*(c>0) instead of c , which evaluates to 0 everywhere where c is smaller than 0. You can also adjust the range of the plot data and colors to only show values that are nonzero. In the case that the data range changes, parts of the plots where the values are outside the range become empty. •It can also be useful to check how the mesh affects the solution by refining the mesh and check if the problem with unphysical values gets better or worse. If it gets better , then continue to refine the mesh. If it gets worse, you probably need to check the physics of the model.。
通讯词汇翻译
半波偶极子 halfwave dipole
半导体存储器 semiconductor memory
半导体集成电路 semiconductor integrated circuit
半双工操作 semi-duplex operation
半字节 Nib
按需分配多地址 demand assignment multiple access(DAMA)
按要求的电信业务 demand telecommunication service
按组编码 encode by group
B
八木天线 Yagi antenna
白噪声 white Gaussian noise
表示层 presentation layer
并串变换器 parallel-serial converter (serializer)
并馈垂直天线 shunt-fed vertical antenna
并行传输 parallel transmission
并行终端 parallel terminal
倒L型天线 inverted-L antenna
等步的 isochronous
等幅电报 continuous wave telegraph
等权网（互同步网） democratic network (mutually synchronized network)
等效比特率 equivalent bit rate
单信号方法 single-signal method
单音 tone
单音脉冲 tone pulse
单音脉冲持续时间 tone pulse duration
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Noise Propagation from Scatter Correction in SPECT MAP ReconstructionParmeshwar Khurd,Santosh Kulkarni and Gene Gindi(1)where is the MAP objective and is a digital projectorused as an approximation to H.Thefinal smoothing termin (1)is characterized by a a scalar that controls the degree of smoothing,and by neighborhood weights .Note that the regularizing term can be written [9]as the quadratic form(2)where is the width of the main energy window andthe width of narrower “satellite”windows placed on either side of the main window.In (2),and are the counts (primary as well as scatter)collected in the left (low energy)and right (high energy)windows.We note that the satellite windows can partially overlap the main window,or that in some cases [5],only a single low-energy window is collected.W mphotopeakW sW Fig.1.The TEW method.The solid curve shows the energy spectrumof scattered plus primary counts.The main window of width and the two overlapping satellite windows of widths are shown.Primary counts in the main window are estimated by subtracting counts in the trapezoid (dotted line).III.T HEORYOur goal is to develop theoretical expressions for the covari-ance and for a measure of resolution,the local point spread function (lpsf)[10],for the reconstruction .These,in turn,will depend on the mean and covariance of and .From (2),the mean and the covariance of the scatter estimate are given bydiag(4)where in (3)and (4),we use the fact that and are Poisson distributed.Note also that the mean and covariance of are given by H H and diag .(Note that the alternative affine form H is used only in the optimization of the likelihood objective.)We use a Taylor series approach to propagate noise from the scatter ing a first-order Taylor series expansion about the mean data and scatter estimate,we get(5)The termis anmatrix whose thelement is given by.Similar definitions obtainforand.An evaluation of the terms in (7)and (8)yieldsdiag(10)diagdiag(13)where we have used the fact that counts in non-overlapping windows are uncorrelated and Poisson distributed.Note alsoin the case of satellite windows that do not overlap the mainwindow,(13)reduces to zero.With(6)-(13),we can now evaluate all four terms in(12).It will be convenient to introduce a Fisher information matrixappropriate for this problem,and this is given bydiagdiag(16)The third term in(12)becomesdiagdiag(18)Using equations(5)-(11),it can be shown that can beexpressed asdiagdiagalong with the approximation in(6).We took of the local background.Figure2(b)shows lpsf profiles for one location.The theory and validation curves match closely.To evaluate the theory expressions for,we used(15)and (16)and the procedures used for obtaining,and.As shown in Fig.2(c)and Fig.2(d),we have evaluated theory expressions for the variance(i.e.the diagonal of)and the local covariance at one pixel(i.e.a column of).As before, evaluation of these terms is equivalent to evaluating terms of the form,and we use rapid Fourier methods to accomplish this.To validate the theory by sample methods,we generated noisy reconstructions and used these to obtain a sample es-timate of variance and local covariance.A total of noisy data realizations was obtained by generating Poisson noise realizations of,and noisy scatter estimates obtained by generating Poisson noise realizations of and then applying(2).Figures2(c)and2(d)show profiles of the sample local covariance and variance images.The correspondence with theory expressions is reasonably close.We are also currently investigating residual discrepancies between theory and sample validations as seen in Fig.2(b), Fig.2(c)and Fig.2(d).We are examining sample-size effects and effects due to a limited number of iterations in the MAP reconstruction.Our hope is that any residual discrepancies are not inherent in the underlying Taylor series approximations.R EFERENCES[1]M.Wernick and J.Aarsvold,Emission Tomography:The Fundamentalsof PET and SPECT.Elsevier Academic Press,2004.[2] F.Beekman,H.de Jong,and S.van Geloven,“Efficient fully3-D iterativeSPECT reconstruction with Monte Carlo-based scatter compensation,”IEEE Trans.Med.Imaging,vol.21,no.8,pp.867–877,Aug.2002. [3] E.Frey and B.Tsui,“A new method for modeling the spatially-variant,object-dependent scatter response function in SPECT,”in Conf.Rec.IEEE Nuc.Sci.Symp.Med.Imaging Conf.,Nov.1996,pp.1082–1086. [4]K.Ogawa,Y.Harata,T.Ichihara, A.Kubo,and S.Hashimoto,“Apractical method for position-dependent Compton-scatter correction in single photon emission CT,”IEEE Trans.Med.Imaging,vol.10,no.3, pp.408–412,Sep.1991.[5]M.King,D.deVries,T.-S.Pan,P.Pretorius,and J.Case,“An investigationof thefiltering of TEW scatter estimates used to compensate for scatter with ordered subset reconstructions,”IEEE Trans.Nuclear Science, vol.44,no.3,pp.1140–1145,June1997.[6]T.Farncombe,H.C.Gifford,M.Narayanan,H.Pretorius,E.Frey,andM.A.King,“Assessment of scatter compensation strategies for Ga-67 SPECT using numerical observers and human LROC studies,”Journal of Nuclear Medicine,vol.45,no.5,pp.802–812,May2004.[7]J.Fessler,“Mean and variance of implicitly defined biased estimators(such as penalized maximum likelihood):Applications to tomography,”IEEE Trans.Image Processing,vol.5,no.3,pp.493–506,March1996.[8]J.Qi and R.Huesman,“Scatter correction for positron emission mam-mography,”Phys.Med.Biol.,vol.42,no.15,pp.2759–2771,Aug.2002.[9]J.Qi and R.Leahy,“Resolution and noise properties of MAP reconstruc-tion for fully3-D PET,”IEEE Trans.Med.Imaging,vol.19,no.5,pp.493–506,May2000.[10]J.Fessler and W.Rogers,“Spatial resolution properties of penalized-likelihood image reconstruction:space-invariant tomographs,”IEEE Trans.Image Processing,vol.5,no.9,pp.1346–1358,Sept.1996. [11]I.T.Hsiao,A.Rangarajan,and G.Gindi,“A new convergent MAP recon-struction algorithm for emission tomography using ordered subsets and separable surrogates,”in Conf.Rec.IEEE Int.Symp.Biomed.Imaging.IEEE,July2002,pp.409–412.Fig.2.(a)Anecdotal reconstruction with data and model(scatter)noise.(b)Profile through row48of slice9of lpsf at one location(48,36,9)(in the background).The sample and theory methods correspond well.(c)Profile through row48of slice9of local covariance image corresponding to voxel (48,36,9).Theory and sample curves are shown.(d)Profile through row48of slice9of the variance image.Theory and sample curves are shown.。