查询词典 threshold

Firstly, based on the force acting on a single-particle, establish a discriminant formula of the sand threshold, and prove that the sand threshold belongs to the cusp catastrophe. Then establish the basic equation of the cusp catastrophe using coordinate transformation and catastrophe theory. Finally, while particle Reynold number and equivalend diameter are the state variables and Shields parameter is the control variables, we can obtain the model of cusp catastrophe of sand threshold, putting those variables into the basic equations of the cusp catastrophe. The model is derived from the mathematics, which has a certain mathematical theory foundation.

首先从单颗沙粒受力分析出发，建立沙床沙粒起动条件判别公式，进而证明了风沙起动属于尖点型突变；然后通过坐标变换和突变理论建立了尖点突变的基本方程；最后本文选择颗粒雷诺数和等效粒径作为控制变量，希尔兹参数作为状态变量，并把它们代入尖点突变的基本方程，经过拓扑变换得到风沙起动的尖点突变模型，并与前人的公式及实验数据进行比较。

Giving two equal-intense stimuli which is higher than the threshold stimulus and whose intervals are longer than the single twich period, two independent contracting curve can be observed. Giving two equal-intense stimuli which is higher than the threshold stimulus and whose intervals are longer than the refractory period, an additive-contracting curve can be observed. Giving several equal-intense stimuli which is higher than the threshold stimulus, tetanus curve can be observed.

当给予两个等强度的阈上刺激，且刺激的间隔大于单收缩的时程，在计算机中可以观察到两个独立的收缩曲线；当给予两个等强度的阈上刺激，且刺激的间隔小于单收缩的时程而大于不应期，在计算机中可以观察到两个收缩曲线的叠加，称为收缩的总和；当给予若干个等强度的阈上刺激，在计算机中就可以观察到强直收缩曲线。

After hot carrier stress, devices were evaluated by using positive bias temperature instability test. With different trends in the time evolution of threshold voltage shift and sub-threshold swing degradation, it is found that electron trapping in the HfO2 is the major reason for the threshold voltage variation. Compared to control devices, devices with fluorine and nitrogen exhibit good passivation at the interface. Devices were measured at an elevated temperature.

在热载子效应后，接著进行正偏压温度不稳定的量测方法，从随时间变动的临界电压以及次临界摆幅，发现临界电压的变动趋势与临界摆幅变动趋势不符合，表示二氧化铪的原生缺陷补捉是造成临界电压变动的主因，而临界摆幅的变动也可得知有氟，氮处理元件具有比较好的介面可靠度。

And a new method determining threshold velocity is proposed. The threshold velocity determining by this method agrees with that by empirical results. Also the relation of the threshold velocity and frequency of explosion is analyzed.

在此基础上提出了一种确定安全速度阈值的方法，并确定了爆破荷载作用下黄麦岭磷矿采场岩质边坡的安全速度阈值，分析了安全速度阈值同爆破荷载频率之间的关系。

In order to conquer the threshold method's shortages,the threshold function is further improved through the simulation of channel's noise based on the translation invariant wavelet,which makes the threshold...

为了克服阈值法的不足，在平移不变量小波阈值去噪法的基础上，通过仿真低压电力线信道噪声，对阈值函数进一步改进，使阈值的变化与噪声的小波变换随尺度的变化特性相一致。

In this dissertation, InGaAs/InGaAsP/InP MQW microdisk laser and its characterization were presented. Some conclusions are as following: the characteristics of lasing threshold was discussed by using rate equation. The dependent relations between threshold and cavity volume, spontaneous emission coupling efficiency β were investigated. The whispering gallery mode and spontaneous emission in a microdisk geometry were then studied. Almost all spontaneous emission was coupled into the lowest order TE mode when the normalized thickness of photonics well was between 0.15 and 0.5. The design principle and device process of InGaAs/InGaAsP/InP MQW microdisk laser were presented. The microdisk lasers with the diameter of 8μm, 4. 5μm and 2μm were succesfully fabricated by using etching techniques. The pulse lasing thresholds for the microdisk with the diameter of 8μm and 4. 5μm were 170μW and 15μW, a record results compared with the published in the literature. The cw lasing threshold for a 2-μm-diameter microdisk was only a few μW. We haven't found similar report up to now. To solve the problem of directional output in a microdisk laser, the power coupling efficiency in a double disk geometry was investigated with the theory of waveguide mode couple. A new structure of electrically pumped microdisk laser with output waveguide was designed, making a foundation for the practical use of microdisk laser.

本文主要研究InGaAs/InGaAsP/InP多量子阱半导体碟型激光器的研制和特性表征，并取得如下结果：利用速率方程理论讨论了激光器激射阈值的特性，分析了阈值与腔体积和自发发射耦合系数β之间的关系；讨论了微碟光子阱结构中的自发发射特性和微碟中WGM模式特性；光子阱结构在其归一化厚度在0.15-0.5之间时，几乎全部自发发射进入到最低阶TE模式中；研究了InGaAs/InGaAsP/InP多量子阱微碟激光器的结构设计原理和器件的制备工艺；利用刻蚀方法成功制备出直径分别为8μm、4.5μm、2μm的碟型微腔激光器；直径8μm和4.5μm的微碟脉冲光泵浦激射阈值分别为170μW、15μW，是目前所见文献报导中比较低的；直径2μm的微碟连续光泵浦激射阈值仅几μW，目前尚未见到达到类似结果的研究报导；为解决微碟激光器激射光定向引出的问题，通过波导耦合模理论分析了双层碟之间功率耦合效率；据此设计了新型带耦合输出波导的电泵浦微腔激光器，为进一步研制可实用的电泵浦微腔激光器打下基础。

The algorithm smooths the gray histogram of the test image with Harr wavelet to remove the "pseudo valley", and fixes a range of the threshold according to the prior information in the standard image, and then finds out the valley of the histogram in the range and that is the threshold. The ex perimental results show that the preprocess algorithm is able to obtain a satisfactory threshold for the binarization of the test image.

该方法使用Harr小波对待测图像的灰度直方图进行平滑处理来消除其中的&伪谷值点&，再充分利用标准图像的先验信息来确定一个二值化分割阈值的大致范围，最后在这个范围内找到直方图的谷值，这即是所需的阈值。

This threshold function has not only overcome incontinuous disadvantage of the hard threshold function, but also solved constant deviation which exists in the soft threshold function, meanwhile the new function needn't selecting parameters.

该阈值函数克服了硬阈值函数值不连续的问题和软阈值函数存在恒定偏差的问题，同时新函数不需要进行参数选择。

Based on having read a great deal of literatures about economic threshold, the authors pointed out the necessity and importance for applying the method of economic threshold in the studies of Phyllostachys pubescens ecosystem in this paper, and the authors also put forward the concept of economic threshold of Phyllostachys pubescens ecosystem and its research frame and some problems which should be pay attention to.

摘 要：在阅读大量有关经济阈值研究文献的基础上，创新地把经济阈值与毛竹林的科学研究结合起来，指出在毛竹林生态系统研究中，应用经济阈值研究手段与方法的必要性和重要性，并提出毛竹林生态系统经济阈值的概念、研究框架及其注意的一些问题，为毛竹林优化经营和丰产培育提供新的思路与技术。

Methods Somatosensory perception threshold, pain perception threshold and the relative pain perception threshold were assessed in 40 patients with chronic low back pain, compared with the findings in a control group and related to the psychopathological state evaluated by means of the Hamilton Depression Scale and the State-Trait Anxiety In-ventory.

比较40例慢性腰腿痛病人与40例正常对照组的躯体感觉阈、痛觉阈及相对痛觉阈，同时对病人组评定汉密顿抑郁量表及状态－特质焦虑量表。

The split between the two groups can hardly be papered over.

这两个团体间的分歧难以掩饰。

This approach not only encourages a greater number of responses, but minimizes the likelihood of stale groupthink.

这种做法不仅鼓励了更多的反应，而且减少跟风的可能性。