查询词典 converters

Laid out with 18 5-ton Bessemer converters - reduced to 11 larger converters in 1879 - and eight larger converters from later date.

阐述了18 5吨贝西默器-减少到1879年在11个较大的转换-从8大以后。

Bilinear system model of DC-DC converters is built, combined with the control objective and extending the system, closed-loop nonlinear control system model of DC-DC converters is found.

首先建立了DC-DC变换器双线性系统数学模型，结合控制目的进行适当变形，得到DC-DC变换器的闭环非线性控制系统模型。

The article makes a comparison among different types of bus, bus transmission signal and several familiar topologies of front-end converters and load-end converters. Finally, the half bridge converter with full-wave rectifier based on the high-frequency parallel-type AC bus bar is chosen as circuit structure and optimized. The working mode under different condition of the circuit is analyzed and a mathematical model is set up under continuous current mode. Simulation result is used as comparison.

通过对比不同类型的母线、母线传输信号以及各种常见的前端变换器拓扑和负载变换器拓扑，确定了基于并联型高频交流母线的半桥变换器加全波整流作为电路拓扑，并优化了电路的结构，分析了基于不同工作状态下的电路结构并建立电流连续模式的数学模型，并与软件仿真结果进行对比。

Furthermore, it is clear that when carrier signal h=0, closed loop PWM DC-DC converters are not well-posed and when some condition is satisfied, closed loop PWM DC一DC converters with P controller are well-posed.

然后利用该结果对PWM型DC-DC降压变换器的适定性的研究表明当载波信号h=O时闭环PWM DC-DC 变换器总是不适定的，当载波信号h的参数和比例控制器的参数满足一定的条件时，比例控制的闭环PWM DC-DC变换器是适定的。

But, in these types of converters, excessive voltage and current stresses occur ,and power density is lower and control is harder than normal PWM converters.

但是， 在转换器的这些类型，过度的电压和现在的压迫力中发生，而且力量密度是比较低的，而且控制是比正常难的 PWM 转换器。

On the basis of the current situation and developing trend of modeling methods of DC-DC switching converters discussed, a circuit averaging method is put forward to model nonideal basic converters operating in the continuous conduction mode.

在对 DC-DC 开关变换器建模方法的现状及发展趋势进行深入分析的基础上，提出了一种非理想基本变换器在连续工作模式下的电路平均建模方法。

For the wavelength assignment in all-optical network, our research include:(1) For the wavelength assignment on ring optical networks with fixed wavelength converters, we use permutation group to study the ability of wavelength converters, and design an assignment algorithm, which can give a good assignment scheme in any general case.

其中，在全光网的波长分配方面，主要包括：（1）对于环形光网中固定波长转换器的情况，采用置换群来刻画转换器的能力，在此基础上提出了一个对于一般情况能够给出较好波长分配方案的算法。

With the development of semiconductor devices, the switching frequency of PWM converters becomes higher, which makes PWM converters (mainly high-frequency transformers, inductors and capacitors in converters) smaller, and this will benefit design and application of them. Whats more, higher switching frequency will reduce the audio-frequency noise and improve dynamic response of PWM converters.

随着半导体器件技术的不断发展，PWM变换器所能达到的开关工作频率越来越高，使得变换器(主要是变换器中的高频变压器、电感等磁性元件和电容)的体积和重量越来越小，这有利于PWM变换器的设计及推广应用。

Some circuits use resonant, quasi-resonant, and/or multi-resonant techniques. However, voltage or current stresses in these converters are higher and require the devices of higher VA rating. Some circuits use passive snubbers or active clamp techniques. However these converters become more complicate. Phase-shift ZVS technique has been used in bidirectional DC/DC converters since it can realize ZVS for all switches without auxiliary switches.

谐振、准谐振或多谐振技术方案，变换器的电压电流应力较高，变频控制增加了滤波器设计的难度；能量缓冲吸收电路或有源钳位电路方案，由于需要增加多个额外辅助元件，增加了变换器的复杂性；全桥相移技术方案，由于主电路无需增加额外元件，只需利用相移控制，即可实现软开关，因此引起关注。

The main purpose of this thesis is to research and develop three different kinds of battery chargers of resonant-switch converters. Starting with the zero voltage switch and the zero current switch converters, which employ the quasi-resonant converter technique, we gain the best parameters of the resonance components from the characteristic curve diagrams of these two converters. Then we design battery chargers based on these two structures and use them to experiment on lead-acid batteries.

中文摘要本论文之主要目的在於研制三种不同的共振开关式转换器蓄电池充电器，先探讨半共振式技术的零电压以及零电流转换器，利用这两种转换器的特性曲线图设计出共振元件最佳的参数值，以这两种架构作为蓄电池充电器，来对铅酸蓄电池做充电测试，经实验测得，零电压切换半共振式降压型转换器之充电器的开关在零电压的时候导通和截止。

The absorption and distribution of chromium were studied in ryeusing nutrient culture technique and pot experiment.

采用不同浓度K2CrO4(0，0.4，0.8和1.2 mmol/L)的Hoagland营养液处理黑麦幼苗，测定铬在黑麦体内的亚细胞分布、铬化学形态及不同部位的积累。

By analyzing theory foundation of mathematical morphology in the digital image processing, researching morphology arithmetic of the binary Image, discussing two basic forms for the least structure element: dilation and erosion.

通过分析数学形态学在图像中的理论基础，研究二值图像的形态分析算法，探讨最小结构元素的两种基本形态：膨胀和腐蚀；分析了数学形态学复杂算法的基本原理，把数学形态学的部分并行处理理念引入到家实际应用中。