直流的

The oscillator circuit of detecting leak current is designed, with which the inductance of detection coil is converted to frequency of oscillatory signal, and the oscillatory signals are used to eliminate the residual magnetism in coil after removal of leak direct current.

所设计的检测电路把敏感线圈电感的变化转换成振荡信号频率的变化，实现了对直流泄漏电流的精确检测，且交变振荡信号又能有效地消除敏感线圈中直流电流引起的剩磁现象。

This reduces the impact of a short circuit and assures that the bus does not conduct current through the aircraft. A Manchester code is used to present both clock and data on the same wire pair and to eliminate any DC component in the signal (which cannot pass the transformers). The bit rate is 1.0 megabit per second (1 bit = 1 μs).

该结构可以削弱短路对总线的影响并保证总线不会传导在航空器中流转的电流。1553总线用曼彻斯特码表示导线对上的时钟信号和数据信号，这可以去除信号中的直流成分，因为直流成分不能通过变压器。1553总线的波特率是1兆位每秒，即每微秒传输一位信号。

Based on the analysis of the affected extent of the neutral-point potential by every space vector on all kinds of voltage and current conditions the concept named neutral point control grade was proposed for the first time in this paper. The calculation formulas of NPCG were presented as well. Based on NPCG, a novel modulation scheme called optimized 3D space vector modulation (O3DSVM) scheme was proposed in a-b-0 coordinates based on the translation principle of axes, by which the space vectors with higher NPCG values are selected to synthesize the object vector to suppress the unbalance of the neutral-point potential.

该文通过对各种电流电压状态下每个三维空间矢量对直流中点电位的影响进行分析，提出了"中点控制度"(neutral-point control grades，NPCG)的概念，并给出了NPCG的计算公式；基于NPCG，在a-b-0坐标系下提出一种基于坐标平移原理的新型"三维矢量优化选择调制策略"(optimized 3D space vector modulation，O3DSVM)，该调制策略能优化选择NPCG值较高的矢量以合成目标矢量，从而达到最大程度控制直流中点电位偏移的目的。

The blushless DC motor has been developed intensly in the latest years. This kind of motors have the merits of both the DC motor and the AC motor, including the high power density and small volume. But it needs a complex and expensive control system, which becomes the biggest obstucle for the blushless motor to be further used.

电气传动域中的无刷直流电机近年来得到了飞速的发展，该电机将交流电机和直流电机的优点相结合，并且具有较高的功率密度和较小的体积，但是其控制系统复杂，代价大，这些都困扰着它在民用领域的进一步应用。

The influent factors to the sensitivity have been reaserched with the values of magnetostriction λ〓, the making and the size of the toroidal core's, heatreatment and so on, and the conversional mechanism between pressure and voltage have been discussed. The experience calculating formula of the sensitivity to pressures was concluded, and it will be useful to the designning and application of the force transducers.

对非晶带的磁致伸缩系数λ〓、环形铁芯的尺寸及制作、热处理等因素对压力—直流电压转换灵敏度的影响进行了研究，并对压力-电压转换的机制进行了探讨，总结出了压力-直流电压转换灵敏度的经验计算公式，对压力传感器的设计和应用提供了依据。

A wind tunnel for thunderstorm downburst was well designed by taking into account the low-speed uniflow wind tunnel design criteria, andan adjustable plate was made to simulate the ground.

鉴于雷暴冲击风试验装置的特殊性以及与低速直流风洞的共通性，参考低速直流风洞的设计方法设计完成了试验装置的洞体结构，并制作了具有调节功能的平板来模拟地面。

Thunderstorm downburst wind tunnel has the particularity and the intercommunity with a low-speed uniflow wind tunnel. A wind tunnel for thunderstorm downburst was well designed by taking into account the low-speed uniflow wind tunnel design criteria, andan adjustable plate was made to simulate the ground.

鉴于雷暴冲击风试验装置的特殊性以及与低速直流风洞的共通性，参考低速直流风洞的设计方法设计完成了试验装置的洞体结构，并制作了具有调节功能的平板来模拟地面。

Taking the development platform of HVDC power transmission for example, the calculation result of impedance-frequency characteristic of traditional line commutated converter and that of FCC are compared. Simulation results show that the impact of impedance-frequency characteristic of converter on the resonance frequency of AC system is not negligible, and FCC can enhance the strength of AC system in a certain extent, improve system stability and effectively reduce AC equivalent impedance under resonance frequency, thus the harmonic instability of HVDC power transmission system can be avoided.

以直流输电开发平台为例，对传统电网换相换流器(line commutated converter，LCC)与FCC的阻抗频率特性计算结果进行对比，仿真结果表明换流器的阻抗频率特性对交流系统的谐振频率有着不可忽略的作用，FCC在一定程度上提高了交流系统强度，改善了系统稳定性，有效降低了系统谐振频率下的交流等值阻抗，从而更好避免直流输电系统谐波不稳定现象的发生。

Simulation results show that this supplementary controller efficiently damps the power oscillation among areas,improves system stability,and has better robustness in various operation modes than the conventional supple-mentary damping controller.

仿真结果表明，与传统的阻尼控制器相比，基于强化学习算法的直流附加阻尼控制器能够有效地抑制区域间的功率振荡，提高交直流系统的动态稳定性，并且对多种运行方式具有一定的鲁棒性。

D According to the new development in the defferential geometric nonlinear control theory and its applications in power systems, a control strategy combined the MTDC modulation and fast steaming valving control is presented. And numerical simulation is adopted to test the usefulness of this control strategy to the transient power systems.

根据微分几何非线性控制理论的新发展和它在电力系统中的应用成果，本文推导了多机交流/多端直流系统的快关汽门与直流调制联合控制的控制规律，并用数字仿真验证了这种控制规律在电力系统暂态过程中的作用。

Do you know, i need you to come back

你知道吗，我需要你回来

Yang yinshu、Wang xiangsheng、Li decang,The first discovery of haemaphysalis conicinna.

1〕 杨银书，王祥生，李德昌。安徽省首次发现嗜群血蜱。