查询词典 mathematical constant

This design separately uses series linear constant voltage circuit, series regulate constant current circuit and the feedback type contravariant circuit to design direct current constant voltage power supply, direct current constant current power supply and DC-DC converter.

本设计分别用串联型线性稳压电路，串联调整式稳流电路和反馈式逆变电路设计直流稳压电源，直流稳流电源和DC-DC变换器。

A sound style rule bars the instructions of a program from using any numerical or textual constant directly; instead, they rely on symbolic names, and the actual values only appear in a constant definition (constant in Pascal or Ada, preprocessor macros in C, PARAMETER in Fortran 77, constant attributes in the notation of this book).

一条合理的规则禁止把任何数字或本文常数直接地使用在程序的指令中；而是依赖于符号名，并且真实的数值只在一个常数定义中出现Pascal或Ada的常数(constant，C的预处理程序宏， Fortran 77的叁数，在本书符号中的常数属性。

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In the first part, we discuss the properties of solutions of (0.1) system with dif-ferent diffusion coefficient and the second boundary condition. The stability of non-negative constant solutions is given, some prior-estimate of the positive steaystateare proved by using the maximum principle and lower-upper solutions, the non-existence of non-constant positive solution, the global exitence of non-constant pos-itive solution and bifurcation solution of non-constant positive steady-states areobtained.

第一章讨论了系统(0.1)在扩散系数不相同的情况下非负常数解的稳定性，运用极值原理，上下解方法确定了系统(0.1)正平衡态解的一些先验估计，然后讨论了非常数解的不存在性，非常数正平衡态解的全局存在性及非常数正平衡态的分歧解。

The stable and constant control system of semiconductor laser diode includes constant current control, constant power control and constant temperature control.

半导体激光器稳恒控制系统包括恒电流控制、恒功率控制和恒温度控制三个方面。

This paper reviews the kinetic mechanism of acetylcholinesterase, illustrates the principle and application of the kinetic parameters such as Michealis-Menten affinity constant Km, maximum reaction velocity Vmax, turnover number Kcat, bimolecular rate constant Ki, affinity constant of the inhibitor for the a ctive site Ka, phosphorylation or carbamylation rate constant K2, and discusses the potential practical application benefiting from the study of the kinetic analysis.

综合评述了AChE的动力学机制的发展状况，着重介绍了米氏常数Km、最大反应速率Vmax、转换率Kcat、双分子速率常数Ki、抑制剂化合物对AChE活性部位的亲和力常数Ka、磷酸化或氨基甲酸化速率常数K2，这些动力学参数的原理及其应用状况，探寻了动力学机制将带来的实际应用。

In the light of the complex, high-level and non-linear feature of the mathematical model which describe the transport of the coalbed methane, this paper study the fully-implicit solving method of the mathematical model in detail. Based on the complexity of the algebraic equations which are formed eventually, according to the alternating direction implicit difference pattern, this paper use the iterative method and the fully main element Gauss-Jordan eliminating method to solve equations, which is to use the iterative method to determine coefficient matrix and use the fully main element Gauss-Jordan method to solve th linear algebraic equation group, at the same time of studying the solving method of the mathematical model, according to the devising requirement of FORTRAN77 program structure, this paper draw up computer program and form the corresponding computer model, and verify the validity and reliability of the model in theory by operating the model.

重点研究了模型内、外边界及有关参数的处理，针对描述煤层甲烷运移的数学模型是一个复杂、高阶非线性数学模型的特点，详细研究了模型的全隐式求解方法，根据最后形成的代数方程组的复杂性，按交替方向隐式差分格式，采用迭代与全选主元高斯约当消去法相结合的方法求解方程：即确定系数矩阵采用迭代法，求解线性方程组时采用全选主元高斯约当消去法，在研究模型解法的同时按FORTRAN结构化程序设计的要求，编制计算机程序，形成相应的CBMRS计算机模型，并通过模型的运行从理论上证明了模型的正确性与可靠性。

The results from confirmatory factor analysis indicated:(1) The structural model of children's early mathematical ability was reasonable and it had good structural validity. In detail, children's early mathematical ability was explained by number, arithmetic, measurement, space/geometry and pattern;(2) The structure of children b early mathematical ability was stable across different ages but the structural model was not consistent completely;(3) Boys' structural model was identical with that of girls'.

经验证性因素分析发现：(1)儿童早期数学认知能力的结构模型是合理的，可接受的，具有较好的构想效度，具体讲，数、计算、测量、空间／几何和模式认知能力五个维度共同解释著儿童早期的数学认知能力；(2)不同年龄儿童早期数学认知能力的结构具有稳定性，但是结构模型並不完全一致，某些项目的解释率有所不同；(3)男、女儿童早期数学认知能力的结构模型具有一致性。

Mathematics: Understands and applies basic and advanced properties of the concepts of geometry; Use the Pythagorean theorem and its converse and properties of special right triangles to solve mathematical and real-world problems; Understands the basic concepts of right triangle trigonometry (e.g., basic trigonometric ratios such as sine, cosine, and tangent); Uses trigonometric ratio methods to solve mathematical and real-world problems (e.g., determination of the angle of depression between two markers on a contour map with different elevations); Uses properties of and relationships among figures to solve mathematical and real-world problems e.g., uses the property that the sum of the angles in a quadrilateral is equal to 360 degrees to square up the frame for a building; uses understanding of arc, chord, tangents, and properties of circles to determine the radius given a circular edge of a circle without the center

数学：理解和应用几何概念的初级和高级特性；用毕德哥拉斯定理、逆定理以及特殊直角三角形性质解决数学的和现实世界的问题；理解基本的直角三角形三角比；运用三角比方法解决数学的或现实的问题。（等高线图上的两个标记之间的俯角确定）运用形体之间的关系及其属性解决数学的或现实的问题（利用四边形内角和等于360度来为建筑物框架取正，运用弧，弦，切线和圆的性质确定缺少中心的一段圆弧的圆心

Due to its good effect in the reservation of information of signal abrupt change, mathematical morphology is often applied in the detection and location of short-term power quality disturbance, however, there is still a defect of invalid detection existing in partial detection methods based on mathematical morphology while some zero-crossing disturbances are detected. In this paper three mathematical morphology based disturbance detection and location methods, i.e., the method based on first-order derivation and morphological gradient, the method based on morphological gradient and soft threshold processing and the method based on dq decomposition and top-hat transform, are analyzed, that is, by means of simulation the adaptability of these methods in the analysis on the signals of voltage sag, voltage swell and electromagnetic transient oscillation is compared.

数学形态学因其在保留信号突变点信息方面有很好的效果，因此常用于短时电能质量扰动的检测和定位，但基于数学形态学的部分方法仍存在对某些过零点扰动检测失效的缺点，文章分析了3种基于数学形态学的扰动检测和定位方法，即基于1阶求导和形态梯度的方法、基于形态梯度和软阈值处理的方法、基于dq分解和高帽变换的方法，通过仿真比较了3种方法在分析电压暂降、电压暂升、电磁暂态振荡等信号方面的适应性，结果发现基于dq分解和高帽变换的方法在检测过零点扰动时具有很好的效果，因此选取这种方法对实测扰动数据进行了检测和定位分析。

A carrier gas such as nitrogen is directed through line 20 and valve 22 to connect with line 26 and mix with the gas sample.

如氮气之类的载体通过管线20和阀22引入，与管线26相通，与气体样品混合。

But for the most part, knaves and parasites had the command of his fortune

然而支配他的家产的大多是恶棍和寄生虫。