查询词典 signal to noise ratio

This thesis mainly discuss following issues, Theory and simple expressions for array covariance matrixes are derived when angular spread functions are symmetric distribution functions, i. e. the Uniform distribution, the Gauss distribution, the Laplace distribution and the Von Mises distribution, and a non-symmetric distribution function, i. e. the Gamma distribution. And the relation between the effective signal subspace and the array number, or and the nominal angle of the distributed source, the angular spread, the distributed functions, and the Signal-to-Noise Ratio is gained. The dimension of the effective signal subspace increases with increment of the array number. And it is more obvious to the non-symmetric distribution. The dimension of the effective signal subspace decreases with increment of the nominal angle. And the distributed source is equal to a point source as θ=π/2. The dimension of the effective signal subspace increases with increment of the angular spread.

本论文针对阵列信号处理中广泛存在的分布源现象，主要讨论了以下问题：推导了角度分布函数分别为对称的均匀分布、高斯分布、拉普拉斯分布、Von Mises分布和非对称的伽马分布时，分布源阵列接收信号协方差阵的严格模型和简化模型，得到了单个分布源的有效信号子空间随阵元数、分布源中心角、分布角、角度分布函数和信噪比的变化规律：随着阵元数的增加，对所有角度分布函数的有效信号子空间维数也随着增加，且非对称分布函数的有效信号子空间充满整个空间的可能性更大；随着分布源中心角逐步增加，有效信号子空间维数逐步减小，当θ=π/2时，等价于点源情形；随着分布源分布角逐渐加大，有效信号子空间维数也随之增加，直到有效信号子空间充满整个空间；随着信噪比的增加，有效信号子空间维数有一定程度的减少。

In order to decrease the measuring error of signal processing in laser Doppler velocimeter, frequency spectrum correction methods for lacer Doppler signal were proposed. Basic principles of energy centrobaric correction, ratio correction and phase difference correction were expounded. The three methods processing ideal sinusoidal signals was simulated with different signal frequencies, and so was the ratio method processing sinusoidal signals with different noises and signal to noise ratios.

在激光多普勒测速仪中，为了减小由信号处理算法带来的测量误差，提出运用频谱校正算法对多普勒信号的频谱进行校正，详细阐述了能量重心法、比值法和相位差法3种离散频谱校正算法的基本原理，运用这3种算法对理想正弦信号进行仿真，并运用比值法对信号施加不同频率和信噪比的噪音下的正弦信号和实测的多普勒信号进行仿真及实验研究。

The module of Zone Abnormal noise Processing ofOMEGA sps is an effective mothod of suppressing noise in Shot gather and CMPgather.②The noise of alternating current is suppressed by notching filter in theseismic data which dominating frequency is far from 50Hz.Otherwise,it issuppressed by mono-frequency noise suppression in the time domain of CGGsps;③The module of F-X Coherent Noise Suppression of OMEGA sps isa good mothod to suppress coherent noise.

此方法在炮域和 CMP 道集上应用效果最好；②对于工业干扰，原始资料主频远离 50Hz 时，采用陷波的方法较为简便，否则采用CGG 系统中的时间域单频压制方法；③对于相干噪音压制，OMEGA 中的频率-空间域相干噪音压制方法在知道斜干扰视速度的情况下，应用效果明显。

Content included: study on the relationship between noise and cumulative noise exposure as well as low frequency noise-induced hearing loss and high frequency noise-induced hearing loss; study on the relationship between noise sensitivity as well as LFNIHL and HFNIHL.1 Study on the relationship between noise and CNE as well as LFNIHL and HFNIHL657 data concerning workers' hearing check-up were collected including such types of work as Trial pilots and Riveters.

内容包括：噪声和累积噪声剂量与语频和高频听力损伤关系的研究；噪声敏感与语频和高频听力损伤关系的研究。 1 噪声和累积噪声剂量与语频和高频听力损伤关系的研究选取成都某大型飞机制造厂试飞和铆工两个工种作业人员657名作为研究对象。其中试飞员199人(均为男性；年龄23～60岁，平均37.36岁；接噪工龄1～42年，平均接噪工龄17.68年)。

KIR bind corresponding HLA-Ⅰmay hame four results followed:1、When inhibitory KIR bind HLA-Ⅰand there has no activatory KIR bind it,cell isn\'t dissolve because inhibitory signal access was done;2、When activatory KIR bind corresponding HLA-Ⅰand there has no inhibitory KIR bind it,form activate signal,lead cell dissolve.3、If activatory or inhibitory receptor both bind HLA-Ⅰ,both signal access is make done,when activatory signal play the main role,NK cell still actived,lead target cell dissolve.4、If activatory or inhibitory receptor both bind HLA-Ⅰ,both signal access is make done,when inhibitory signal play the main role,or both signal access don\'t play,NK cell do not make effect.this is NK cell recognice nomal tissue.

与活化型KIR受体相比，抑制型KIR受体与HLA-Ⅰ类抗原结合的亲和性更强，当抑制型和活化型KIR受体识别和结合同一HLA-Ⅰ类抗原分子时，以抑制作用为主。KIR与相应HLA-Ⅰ结合后可能产生以下4种情况：①当抑制型KIR与HLA-Ⅰ结合而无活化型KIR与HLA-Ⅰ相互作用时，因抑制信号通路启动而不产生细胞溶解；②当活化型KIR与靶细胞表面的相应HLA-Ⅰ结合同时无抑制型KIR与HLA-Ⅰ的相互作用时，形成刺激信号通路，导致靶细胞溶解。

The frequency of particular amino acids in signal peptides by statistical approach was 48.54% for hydrophobic, 18.67% for uncharged, 24.54% for negative and 8.00% for positive amino acids. The most frequent amino acid was alanine, and the least was isoleucine. Three classes of signal peptides were found in the genome of P. syringae pv. tomato, 501 ORFs belong to secretary signal peptides, 36 ORFs belong to twin-arginine signal peptides, and 15 ORFs belong to lipoprotein signal peptides. Type IV pilin signal peptide and bacteriocins and pheronones signal peptide was not found in the genome.

同时，对组成信号肽的氨基酸种类作了系统的分析，发现组成信号肽的氨基酸中非极性氨基酸占48.54%，极性氨基酸占18.67%，带负电荷氨基酸占24.54%，带正电荷氨基酸仅占8.00%，出现最多的3种氨基酸依次为亮氨酸、丙氨酸和丝氨酸，最少的氨基酸是异亮氨酸，在切割位点－1端的氨基酸中83.21%均为丙氨酸，在切割位点后3位的氨基酸中最多的氨基酸也是丙氨酸。

The treating plant mainly has the following input signal in this set of control system: Che Neinei was mad that outside the temperature signal, the vehicle the external Qi temperature signal, the water temperature temperature signal, the air blower feedback signal, the mix air throttle feedback signal, the back light lamp signal and so on, the output device is the VFD fluorescence vacuum display monitor, the control device is mainly on control panel''s pressed key, realizes the plan acts according to the vehicle speed, Each temperature value''s situation comes the intelligent control air-conditioning system various air throttles electrical machinery and compressor''s work, causes in compartment''s temperature basis hypothesis temperature in the physical sensation comfortable scope, simultaneously controls the blowing through the air throttle electrical machinery''s movement the direction, the cold hot blast proportion, the automatic control, forces to defrost, the inside and outside circulates the wind transformation and the breakdown situation demonstration is the concrete function which this set of control system can realize.

在这套控制系统中处理装置主要有以下输入信号：车内内气温度信号、车外外气温度信号、水温温度信号、风机反馈信号、混合风门反馈信号、背光灯信号等，输出装置为VFD荧光真空显示屏，控制装置主要是控制面板上的按键，实现的方案是根据车速，各个温度值的情况来智能控制空调系统各风门电机和压缩机的工作，使得车厢内的温度根据设定温度在人体感觉舒适的范围之内，同时通过风门电机的动作来控制吹风的方向、冷热风的比例，自动控制，强制除霜，内外循环风的转换和故障情况的显示都是这套控制系统所能够实现的具体功能。

The results of the study showed that:① Using dozens of kilograms of explosives the signal can be detected at distances up to 200 km;②Active source has a certain degree of repeatability among different shots;③This paper presents the following shooting mode and signal detection method based on the similarity of different shots: In light of the similarity between the signals of big shot and small shot, this paper presents a cross-correlation method using signal from big shot signal with high SNR and small shot signal to detect weak small shot signal, the method can effectively detect the small shot signal and pick up the start time of phase, this method can help us make full use of past seismic exploration data records.

野外实验采用1次大当量激发和16次小当量激发，研究结果表明：①有可能利用数十公斤当量的炸药实现200km距离的探测；②在激发条件相同时，不同当量的激发波形滤波后存在一定的相似性；③依据人工震源可重复性采用以下的激发组合方式和处理方法能够有效提高信噪比：针对大当量激发与小当量激发波形的相似性，利用大当量激发的波形作模板与小当量激发的波形作相关，可判断台站是否接受到小当量激发的信号并检测其震相到时信息。

Aiming to solve the shortcoming in the prior art that any on-line DCF dispersion compensation technology is not provided for long distance, and the nonlinear effect in the dispersion compensation technology is restrained, the invention provides the dispersion compensation method, which includes the steps that after a sending end implements electric pre-compensation treatment on a digital signal to be transmitted, a control electric/optical converter module outputs a distorted optical signal; after receiving the optical signal, a receiving end conducts a post compensation treatment after converting the optical signal into an electric signal, or converts the optical signal into the electric signal after implementing the post compensation treatment.

为了解决现有技术中长距离无在线DCF色散补偿技术的不足和抑制色散补偿技术中的非线性效应，本发明提供了一种色散补偿方法，包括发送端将待发射的数字信号进行电预补偿处理后，控制电/光转换模块输出畸变光信号，接收端收到光信号后，将光信号转换为电信号后进行后补偿处理，或将光信号进行后补偿处理后转换为电信号的步骤。

Correctional checking formula of melt flow ratio in injection molding was obtained by introducing a correction coefficient β which reflected the complexity degree of mold cavity. The results show that, the maximum flow ratio of 486 can be obtained when injection pressure ranges from 150 MPa to 160 MPa in Archimedes spiral mold for PP, while maximum flow ratio of 419 can be obtained when injection pressure ranges from 160 MPa to 170 MPa for PE. There is a local fluctuation phenomenon for flow ratio and corresponding injection rate in square spiral mold when injection pressure of 100, 120 and 150 MPa for PP and 130, 140 MPa for PE are reached respectively,and this phenomenon is more serious for good fluidity of melt. The average flow ratio in Archimedes spiral mold is 6% larger than that in square spiral mold for PP, and 4% for PE, the average flow ratio of PP is 19% bigger than PE in Archimedes spiral mold, and 15% in square spiral mold. The influence of the cavity profiles on the melt flow ratio is more significant for good fluidity of melt.

研究结果表明：在阿基米德螺旋线模具中，PP在注射压力为150~160 MPa时取得最大流动比485，PE在注射压力为160~170 MPa时取得最大流动比419；在方形螺旋线模具中，PP在注射压力为100，120和150 MPa，PE在注射压力为130和140 MPa时流动比及所对应的注射速率出现波动，且流动性好的熔体波动更为严重；PP在阿基米德螺旋线模具中的流动比均值较其在方形螺旋线模具中大6%，而PE大4%；在阿基米德螺旋线模具中流动比均值PP比PE的流动比均值大19%，而在方形螺旋线模具中PP的流动比均值比PE的大15%；流动性好的熔体受模具型腔轮廓特征影响大。

Objective:To explore the feasibility of laparoscopy in diagnosing and treating of abdominal diseases.

目的：探讨腹腔镜用以诊断腹部外科疾病及选择治疗方案的可行性。

The lifetime of nylon 1010 and nylon 1010/POSS composites decreased with increasing temperature.

热重-红外联用分析表明尼龙1010在氮气气氛下的降解产物主要为小分子的低聚物，POSS并不改变尼龙1010降解产物的组成。