查询词典 constant current

From the junction temperature-varied optical properties measurement, we find that the luminous efficiency will decay more quickly at low current operation. However, when the current density increases to the saturation capacity of the quantum well, the decay ratio will reach a constant.

在变温的光学特性量测上，由实验结果发现，发光效率在较低电流时会衰减的较快，然而在注入电流达到量子井的饱和量后，其发光效率随接面温度升高衰减的现象则会趋近於固定的比例。

More than 50 GaAs/GaAlAs High Power Single Quantum Well Semiconductor Lasers are aged. The threshold current decreases during the early aging (first 520 h) and the largest decrease is 57 mA. From the aging result of more than 1000 h at constant current, we find that output power increases during the early aging , and then decay slowly according to exponent law.

通过对50余只808nm的GaAs/GaAlAs高功率单量子阱远结半导体激光器的老化实验观测，在老化初期（前520h），阈值电流随老化时间的延长而下降，下降幅度高达57mA，从1000h多的恒流电老化结果可以看出，器件的输出光功率在老化初期有所上升，随后，表现出按指数规律缓慢下降的行为。

What this paper finished mainly work as follows: Five-phase hybrid step motor driver system with fixed-chopping frequency and constant total current driving is fully described. Mathematical model of the system, included the current control circuit, power driving circuit and five-phase hybrid stepping motor is established. The steady modeling of the system is established and studied. Based on the steady modeling of the system, dynamic modeling of the system is studied and single step response characteristic is constructed with MATLAB/Simulink. The simulation results, which is certified by the theory analysis, coincide with the theory analysis.

本文主要完成的工作包括几个方面：对五相混合式步进电动机恒频斩波恒总流驱动系统进行了完整的描述；建立了包括电流控制电路、功率驱动电路以及五相混合式步进电动机在内的恒频斩波恒总流驱动系统的完整的数学模型；基于MATLAB/Simulink建立了恒频斩波恒总流驱动系统稳态仿真模型，并进行了仿真；在建立其稳态仿真模型的基础上，对动态模型进行研究，并借助于MATLAB/Simulink工具建立了恒频斩波恒总流驱动系统单步响应特性的仿真模型并对其单步响应特性进行了仿真研究，仿真结果与理论分析相符。

Well, the α ratio works similarly: if emitter current is held constant, collector current will remain at a stable, regulated value so long as the transistor has enough collector-to-emitter voltage drop to maintain it in its active mode.

系数α的作用与之类似：如果发射极电流保持恒定，只要集电极－发射极电压足以使其保持在放大区，集电极电流也将稳定保持。

In Chapter 2,the polarization and loss mechanism of fruit in the alternating current arestudied,and dielectric parameters such as dielectric constant、equivalent impedance andequivalent capacitance are put forward to analyze the interaction between fruit internalquality and alternating current.

第二章 研究了水果生物介质在交变电场作用下的极化和损耗机制，提出了复介电常数、等效阻抗及等效电容几个相互联系又有所区别的电特性参数是研究交变电场与水果相互作用的基本参数。

Points out that the switching frequency、the input inductance and the output power all have great contribution to the input-current THD. When the output power goes up, the input current harmonic content keeps almost constant, thus the THD goes down.

指出开关频率、输入电感和输出功率对输入电流THD有显著影响，发现整流器输出功率增加时，输入电流谐波含量基本不变，从而输入电流THD减小。

Current tuning is introduced, and the speed open-loop transfer function is established based on current closed-loop. A mathematical inequation about the speed open-loop transfer function is deduced, then the measured amplitude-frequency data is introduced in the inequation, thus the mathematic expressions about moment of inertia and mechanism time constant are obtained.

引入了电流校正环节，建立了基于电流闭环的速度开环传递函数，推导了关于该速度开环传递函数的数学不等式，再将实际测得的幅频特性代入此不等式中，得到了关于转动惯量和机械时间常数的数学表达式。

It is, again, helpful to use the magnetizing current As explained earlier, the magnetizing current imq can be approximated to be constant.

这是一次有益的利用激磁电流说过磁化电流过量可近似为常数。

Methods Retrospective analysis of 120 cases with multi-slice abdominal CT scanning were randomly and equally divided into experimental group and control groups, which group was 60 cases, respectively using automatic tube current modulation techniques and constant tube current in abdominal CT examination, the statistics were weighted CT dose index, dose-length product and effective milliampere seconds to compare image noise characteristics and the details show results.

回顾性分析我院腹部多层螺旋CT检查120例，随机分为实验组与对照组各60例，分别采用自动管电流调制技术和固定管电流技术进行腹部CT检查，分别统计CT剂量权重指数、剂量长度乘积及有效管电量，并对图像噪声特性、细节显示结果进行比较。

This paper instructed the numerical control DC constant current source which makes use of the AT89C51 version single chip microcontroller is the main controller in this system, while the set value and the real output current can be displayed by LED.

本文介绍了采用AT89C51单片机为主控制器，通过键盘来设置直流恒流源的输出电流，并由数码管显示电流设定值的数控直流恒流源。

I hope that this success is just the first in a long series.

我希望这只是成功的开始。

Three dimensional stresses on the interface of tire and soil, tire deflection and soil sinkage are measured.

测试轮胎——沙土界面上的三向应力、轮胎变形和沙土沉陷；建立考虑剪切应力对沙土承载特性产生影响的车轮牵引性能预测模型；分析车轮作用下土壤的纵向稳定性。