微弱

In the paper, the theory and methodology of amplitude correction method using average of several points in discrete spectrum, which is suitable for analyzing the dynamic signals of rotating machinery with small varying speed, is proposed and systematically studied.

系统而完整地提出了处理变速机械弱时变响应信号的离散频谱多点平均幅值修正法的理论和方法，严格证明了该方法能精确地计算出平稳信号和频率微弱波动信号的幅值，能近似地计算出幅值和频率均微弱波动的信号的平均幅值，并应用这套理论成功地解释了频率微弱波动信号的幅值谱表现出较严重的"功率泄露"效应的原

By analyzing the faultiness of the wavelet method used in processing signal denoise and detection of weak signal.

通过分析小波变换处理信号噪声的方法及其在微弱信号检测方面的不够完善之处，提出适合于极低信噪比条件下小波消噪法的信号检测原理和方法，即通过构造具有可调功能的阈值函数以及对小波分解系数处理方式的优化设计等方法，在强背景噪声中提取出微弱的信号特征信息，从而实现微弱信号的检测。

Aiming at difficulty of weak impactive roller bearing fault feature extraction of composite faults, a demodulation method based on the second generation wavelet and the empirical mode decomposition is proposed to separate the coupling features of a composite fault and to extract the fault feature of a roller bearing.

针对复合故障中滚动轴承微弱冲击性故障特征难于提取的问题，提出基于第二代小波和EMD的解调方法，进行复合故障的耦合特征分离和轴承损伤性故障微弱信号的特征提取研究。

aining at high impedance weak signal measurement,the relations among measuring precision,input impedance and input bias current,the guard technology is applied to design a measuring circuit with guard circuit,adding a guard potential to low-impedance nodes of circuit,the effect of leakage current is reduced.using spice simulation and validates that guard circuit can increase the input impedance of the system and lower the input bias current,the results show that the guard circuit provids a valuable solution for high accuracy measurement of the high impedance weak signal.

摘 要：针对高阻抗微弱信号测量问题，对测量精度与系统输入阻抗、输入偏置电流的关系进行分析，应用保护技术设计了带保护电路的测量电路，将电路中的低阻抗节点加上保护电势，减小漏电流的影响。通过pspice仿真分析，验证保护电路能提高测量系统的输入阻抗和降低输入偏置电流，结果表明保护电路技术能实现对高阻抗微弱信号的高精度测量。

They form a polar molecule, that is, one with a slightly positive end and a slightly negative end.

它们形成一个极性分子，也就是说，一个带有微弱正电荷和微弱负电荷的极性分子。

Besides these, the present calculations indicate that the epoxidation of ethylene is slightly endothermic or exothermic in sextet and quartet states, respectively.

另外，我们的计算结果显示乙烯环氧化反应在六重态下是微弱吸热的，而在四重态下是微弱放热的。

An information fusion technology was successfully coupled to the analysis of original weak electrical signals in Bellis perennis, which consisted of a touching testing using platinum sensors in a system of self\|made double shields, the signals denoised by the wavelet soft threshold and a forecast system of time series by the autoregressive integrated moving average constructed with plant characters of electrical signals.

将自制的具有铂金传感器的双重屏蔽微弱电信号测试系统，所获取的植物微弱电信号、小波软阈值消噪、时间序列的求和自回归移动平均模型等单因素分析耦合成信息融合技术，对雏菊电信号时间序列进行了数据融合分析预测。

The character of original weak electrical signals in Crassula portulacea was tested by a touching testing using platinum sensors in a system of self-made double shields.

利用自制的屏蔽室和屏蔽箱以及自制的铂金传感器接触式微弱电信号测试仪，初次获得了燕子掌自适应微弱电信号特性。

FGFR4 expression was faint in renal vesicle and primitive tubules of S-shaped body, irrecognizable in urteric bud and podocyte of C-stage, negative in mesenchyme and condensing mesenchyme.

胚胎肾发生带内FGFR4表达微弱，肾囊泡和S型小体的上支和中间支，即原始肾小管上皮细胞部位有微弱表达，间充质、压缩间充质未见表达，输尿管芽及其末端壶腹和C-期足细胞表达不明显。

The fiber length has only little influence on the basic density within the growth rings, and significant correlation at 0.01 levels was found between the basic density and the fiber length among the different rings. Only slight negative correlation was found between the basic density and the fiber width within the growth rings, but significant positive correlation at 0.01 levels was indicated between the basic density and the fiber width among the growth rings, contrary to that of fiber length. It was demonstrated that significant positive correlations at 0.01 levels between the basic density and fiber double wall thickness, fiber length to width ratio and double wall thickness to diameter ratio, significant negative correlations at 0.01 levels between the basic density and fiber diameter and diameter to width ratio, only slight negative correlation between the basic density and fiber width both in the same growth rings and among the different growth rings. No significant correlation was found between the basic density and the vessel morphological features, nor was the tissue proportion in the same growth rings. But among the different rings, it was found there was significant positive correlation at 0.01 levels between the basic density and the fiber proportion among the different rings, and significant negative correlation at 0.01 levels between the basic density and vessel-elements proportion and ray proportion, only slight negative correlation between the basic density and the parenchym proportion. Significant or no significant negative correlation was found between the basic density and the microfibril angle in the same growth rings, but significant negative correlation was found between the basic density and the microfibril angle among the different growth rings.

生长轮内纤维长度对基本密度的影响不大，而在不同生长轮间纤维长度与基本密度达极显著正相关，纤维宽度与此相反，同一生长轮内纤维宽度与基本密度极显著负相关，不同生长轮间只有微弱负相关；基本密度与纤维双壁厚、长宽比、壁腔比在生长轮内和生长轮间均呈极显著正相关，而与胞腔直径、腔径比均呈极显著负相关，仅与纤维宽度呈微弱的负相关；导管形态对基本密度的影响不显著；同一生长轮内组织比量对基本密度的影响也不显著，但不同生长轮间基本密度与纤维比量呈极显著正相关，与导管比量和木射线比量呈极显著负相关，与轴向薄壁细胞比量仅呈不显著负相关；生长轮内基本密度与微纤丝角呈显著或不显著负相关，但在生长轮间这种负相关达到极显著水平。

This one mode pays close attention to network credence foundation of the businessman very much.

这一模式非常关注商人的网络信用基础。

Cell morphology of bacterial ghost of Pasteurella multocida was observed by scanning electron microscopy and inactivation ratio was estimated by CFU analysi.

扫描电镜观察多杀性巴氏杆菌细菌幽灵和菌落形成单位评价遗传灭活率。