查询词典 frequency

This project focuses on the joint time frequency characteristics of different phenomena in different types of fire disaster, such as pool fires, boilover, smoke movement, and different classes of fire. The temperature, optical density, heat radiation, combustion noise, and velocity of thermal flow are analyzed by joint time frequency method.

本项目研究中针对各种火灾场景：如油池火焰在水雾、风作用下的变化、扬沸过程中诸参数的变化、烟气运动过程、各类火焰等进行了实验与分析，对实验中的温度、火焰消光度、热辐射、燃烧噪声、速度分布等参数进行了联合时频域的分析。

The result showed that the volume, dry weight and total sugar content of root gradually reduced with the harvest frequency, but the reductive sugar content in root increased. While the harvesting frequency was two times per year, the volume and dry weight of alfalfa root showed an decreasing at beginning and then increasing when the first harvesting was at different growth stages and the lowest values were at flowering period however, it was not significant for brome.

结果表明：随刈割次数增加，两种牧草根体积、根干重和根部总含糖量逐渐减小，而根系还原糖含量呈逐渐增加的趋势；在年刈割两次，首次刈割分别在不同生育时期试验处理中，苜蓿根体积和干重呈先减后增趋势，首次刈割在盛花期根体积和干物质含量均最低，而无芒雀麦变化不明显。

With rowing box carburize ,glowing furnace,high frequency furnace and medium frequency furnace can meet various requirements for heat treatment.

我厂依靠先进的工艺技术装备、熟练而精细的操作技巧以及可靠的质保体系和优质诚恳的经营作风为产品提供了质量保证。随着企业的发展，如今产品已达30多个品种、300多个规格，能全面满足顾客的要求。

With rowing box carburize ,glowing furnace,high frequency furnace and medium frequency furnace can meet various requirements for heat treatment.

我厂依靠先进的工艺技术装备、熟练而精细的操作技巧以及可靠的质保体系和优质诚恳的经营作风为产品提供了质量保证。随著企业的发展，如今产品已达30多个品种、300多个规格，能全面满足顾客的要求。

Due to existing signal processing technology's shortage such aslow measurement, narrow measurement range precision and other poor performance, we introduced a high-precise signal processing technology:firstly,to get power spectrum with Hanning windowed Welch modified periodogram, search its peak value frequency;secondly, to apply zooming analysis via Goertzel algorithm;at last,to get a highly precise doppler frequency with energy centrobaric rectifying algorithm.

针对存在的缺点，本文提出了一种应用于激光多普勒测速的高精度信号处理技术，即首先利用加Hanning窗的Welch修正周期图算法得到信号功率谱，搜索其谱峰值频率，接着利用Goertzel频谱细化算法对搜索的谱峰进行细化分析，再引入能量重心频谱校正算法对细化后的谱峰进行校正分析，从而将离散频谱分析算法、频谱细化算法和频谱校正算法三者有机结合起来，充分发挥各自的优点：通过加Hanning窗的Welch修正周期图算法快速得到功率谱及峰值频率，通过Goertzel算法获得分析频带的高分辨率频谱，然后通过能量重心校正算法对细化后的频谱进行高精度校正，这样不仅保证了算法的高效性，而且大大提高了分析的精度。

The reader community covers audio frequency worker as the broadcasting station and television station, recording technician, monitor, audio frequency engineer and so on; amplifying system engineer worded in the theater, the stadium, the audiovisual education hall, the conference room; tuning personnel worked in the hotel, choric hall, the multi-purpose hall; and the acoustic fan and the music amateur and so on.

发行范围覆盖音频工程企业、影剧院、体育场、多功能厅、娱乐场所，电台、电视台、网站、科研院所、学校等领域内的工程商、音频工程师、录音师、调音师、学生等，以及音响发烧友和音乐爱好者等。

On the basis of previously research, this paper re-probe into the mechanism of electro-chemist mechanical manufacturing process, making the rational technological parameter, and developing the manufacturing equipment. Through a lot of technology tests, get a lot of labratory data, accordingly, researched the surface feature of the electro-chemist manufacturing process, and deeply discussed its influence on the work piece feature. The last result is that: the electro-chemist mechanical manufacturing process can reduce the low-frequency component significantly, but on high-frequency component, it has little influence, having obviously positive pole flat effect. After manufacture, the tip parts on the surface of the work piece is cut off, there is micro "high land" shape, the parameter for surface roughness is reduced a lot, the surface outline of the work piece is negative, the bearing length rate is cliffy. Also the surface quality of the work piece is improved. This can help to avoid changing the shape, improve the feature of rub, gear and reduce the time to suit. This would also ensure the precision and result in a longer work piece life.

在以前研究的基础上，本论文重新探讨了电化学机械复合光整加工工艺的机理，确定了较合理的工艺参数，对电化学机械复合光整加工设备进行了改进，通过工艺实验广泛地搜集了大量实验数据，依据实验数据，多角度地研究了电化学机械复合光整加工的表面形貌特点，并且从理论上深入讨论了电化学机械复合光整加工表面形貌对工件工作性能的影响，最后得出的结论为：电化学机械复合光整加工对工件原始表面的低频成分有较大程度的降低，而对高频成分影响较小，有明显的阳极整平作用，被加工工件表面的尖峰状凸起被去除，工件表面呈现出微观&高原型&，表面轮廓不平度高度特性参数大幅度降低，工件表面轮廓分布集中，且呈负偏态，轮廓偏斜度为负值，轮廓支承长度率曲线陡峭，工件的表面质量得到综合改善，这对提高零件的抗接触变形能力、改善摩擦、磨损性能、降低工件的磨合时间、提高工件的精度保持性、延长工件的寿命均有利。

After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

The opened magnetic circuit is composed as tow NdFeB permanent magnets and a top plate without U-yoke. After take analyzed deeply for the opened magnet circuit with FEMM (Finite Element Method Magnetics) we find out the field distributing that is separated into three sections . One is the main area what we called as positive field section. Beside the main field there are tow areas that are called the inverted field sections. Loudspeaker arise a very serious distortion when the voice coil moving into inverted field areas. The direction of induced current in the coil part of entered inverted field area is same with the current driving into loudspeaker so that total currents increas largely and heat increase rapidly. With more coils moving into inverted area the voice coil will take on negative inductance properties. It is the main reason that voice coil is burned by heating with increasing current due to arise negative inductance. So opened magnetic circuit is not suitable for the woofers in which the voice coil have wider displacement range. When using this kind magnetic circuit design, the voice coil moving range should be less than the range of positive field to avoid loudspeaker arise serious distortion and heating. Even though voice coil moving range is in the positive area, loudspeaker will still arise more distortion because the field distribution is very cliffy at tow sides of the positive area and full range of magnetic field distribution is not parallel that will arise distortion. Base on above reasons, opened magnetic circuit is not an ideal magnetic circuit for low-frequency loudspeakers. But it can be used in mid-range or high-frequency productions.

开式磁路是由2片钕铁硼磁铁和主导磁板和导磁垫片组成，我们在实践过程中发现这种磁路结构不适合于低频扬声器的使用，我们通过使用FEMM（Finite Element Method Magnetics）软件包对该磁路进行了分析，该磁路的磁场范围被分成3个区域，其中在主导磁板附近形成一个正向磁场，在正向磁场的两边存在反向的磁场，音圈在工作时有很大一部分进入了反向磁场中，在反向磁场内线圈的感应电流方向与驱动电流方向相同，使得音圈呈现出负感抗特性，由于音圈的负感抗特性引起电流的增加导致音圈发热甚至烧毁，因此在扬声器中使用开式磁路时，音圈的运动范围应控制在正向磁场范围之内，否则音圈运动到反向磁场区域时将会产生很大的失真和发热，即使在设计时已经将音圈的运动范围控制在正向磁场范围之内，由于正向磁场的2个边缘磁场强度衰减太快，同时开式磁路中磁场的分布不是平行的，而是自由发散的分布，这样肯定会导致扬声器的非线性失真，因此我们得到的结论是：开式磁路并不是一个理想的磁路，它不适合于低频扬声器的使用，但它还可以应用于中高频扬声器。

Methods In order to realize portability for high-frequency argon-beam coagulatory devices, several high technologies were applied, including microelectronic technology, MCU automatic control technology, new technology of program-controlled high-frequency power switch and technology of argon-beam control for pressure and flow stability.

采用微电子技术、单片机自动控制技术、程控高频开关电源新技术及氩气稳压稳流控制技术，多项高新技术应用于氩束凝固止血器，实现了氩气高频止血设备便携小型化。

Objective: To study the effect of polycythemia on blood oxygen saturation.

裴蕾目的：观察RBC剧增而引起的高粘血症对血氧饱和度的影响。

Based on SIMPLER algorithm in the curvilinear body-fitted coordinates, the calculations were performed for Pr=0.7, Re=10~1000 on non-orthogonal non-staggered grids which are generated by elliptic equation systems.

采用曲线坐标系下压力与速度耦合的SIMPLER算法，数值研究了周期性渐扩渐缩波纹通道内脉动流动与换热情况，流动Re数的范围为10~1000，Pr数为0.7。