高频率的

The ultrasonic emissive circuit is crucial and will affect the system profoundly.

在该流量计的研制过程中，关键是设计重复频率高的超声波发射电路和较高增益、宽频带的超声波接收放大电路。

The method of multilevel parallel phase modulation was proposed, which means two parallel multilevel phase shift keying signals were transmitted with one frequency at the same symbol period.

提出了高阶并行相位调制的方法，即在同一调制符号周期，使用同一频率、并行发送2路携带不同信息的高阶相位调制信号。

It makes the positioning stage not only has high response frequency and move sensitively, but also has high positioning precision.

它将使定位平台既有高的响应频率，动作灵敏，又具有较高的定位精度。

The quantity computed is the expected clutter power at the output of any specified range gate by the method of integrating reflected energy between constant Doppler loci in range-gate circles with a model of sum and difference antenna gain pattern for APAR. Base on the analyzing of APAR terrain clutter spectrum, Rayleigh, Correlated Log-Normal and Weibull distribution terrain clutter of APAR general pulse signal was simulated with the method of zero memory nolinearity transform.④The Doppler frequency of target echo is simulated on video frequency in this dissertation.

该软件采用了用C语言建立框架结构，而在程序高重复部分和有运算速度要求的地方，用汇编语言编写具有高并行能力程序的方法，不仅满足了系统高运算速度和实时性的要求，也使得软件系统结构模块化，代码具有良好的维护性和重用性；③对机载相控阵雷达HPRF、MPRF的和、差通道地面杂波功率谱进行了较为全面的研究，通过建立由四个子波束构成的机载相控阵雷达杂波和差波束天线方向图数学模型，选取体现高度线杂波的修正的地面后向散射模型，以载机平飞为例，采用沿距离门——等多普勒线区域积分的方法，得到了杂波功率谱，并利用零记忆非线性变换法实现了机载相控阵雷达常规脉冲情况下瑞利分布、对数正态分布和韦布尔分布地面杂波的模拟；④提出了采用在视频上对目标回波的多普勒频率进行模拟的方法。

The multipath effect is an avoidless problem which the tracking radar and the searching radar among CIWS has to face. This paper analyses the form of the multipath effect on geometry, emphasizes the distance difference between the direct wave and the reflected wave, according to this inherent characteristic, the paper introduces the theory of HRR to the design of radars among CIWS, discusses the spike pulse technology and ultra wide hand technology which often be used, finally proposes the method of time-frequency code to obtain the high range resolution and avoid the multipath effect.

多路径效应是近程反导武器系统中的搜索雷达和跟踪雷达均无法避免的问题，文中分析了多路径效应形成的几何原理，并根据多路径效应中的直射波与反射波具有路程差的固有特性，将高距离分辨率雷达信号理论引入到近程反导武器系统的雷达中，讨论了实现高距离分辨率的窄脉冲和超宽带技术，最后提出了目前较易实现的时间－频率码合成高距离分辨率的办法。

Seven Brachionus species in Lake Jinghu were found, of which Brachionus calycflorus, B. angularis, B.diversicornis and B.forficula were determined as common species due to their higher population densities and occurrence frequency. The population density of both B.calyciflorus and B. angularis reached the peak in February and March and decreased rapidly after April, while that of both B. diversicornis and B. forficula remained high during June-September and decreased sharply after October.

结果表明，镜湖常见的7种臂尾轮虫中，仅萼花臂尾轮虫、角突臂尾轮虫(B.angularis)、裂足臂尾轮虫(B.diversicornis)和剪形臂尾轮虫(B.forficula)的种群密度和出现频率较高；前两者种群密度高峰期均出现在2~3月份，4月份后均较低；后两者种群密度在6~9月份较高，而在10月份后很快下降。

objective to evaluate efficacy of extracorporeal shock wave lithotripsyfor treating ureteral stones in situ,investigate the cause of higher re-treatment rate.methods total of 687 patients with ureteral stone were received eswl between january 2000 and december 2004,included 455 male(66.2%) and 232 female(33.8%) patients,6 cases have bilateral ureteral calculi,12 cases have unilateral multiple calculi.hence,together 709 ureteral calculi were treated.patients upper ureteral calculi were treated in the supine position,for lower ureteral calculi patients were turned prone.to reduce eswl-induced renal trauma and pain,using lower energy source,adjusted power setting from 9.8 to 13.2kv,limited 1500 shock wavs per one session.no auxiliary procedure were used before eswl.the stone size was measured as the surface area of stone length by stone width on x-ray film.the interval between two treatment sessions was two weeks.results of 709 ureteral calculi,the overall stone free rate was 97.3%(690 calculi),re-treatment rate was 34.1%(292 calculi).according to the performed treatment sessions,one session 467 calculi,the mean stone size 37.27mm2,stone free rate 65.4%(464 calculi).two sessions 138 calculi,the mean stone size 62.48mm2,stone free rate 18.4%(131calculi).three sessions 52 calculi,the mean stone size 79.60mm2,stone free rate 7.1%(50calculi).four sessions 19 calculi,the mean stone size 101.63mm2,stone free rate 2.4%(17calculi).fivesessions 33 calculi,the mean stone size 119.33mm2,stone free rate 3.9%(28 calculi).overall 19 cases(2.7%)turned to other treatment modalities.of 335 upper ureteral calculi,303 achieved stone free (95.8%),re-treatment rate was 38.5%(129 calculi).of 374 lower ureteral calculi,369 achieved stone free(98.7%),re-treatment rate was 30.2%(113 calculi).the re-treatment rate of upper ureteral calculi was higher than lower ureteral calculi(p＜0.05,χ2=5.40).the difference of stone-free rate between upper and lower ureteral calculi was no significant(p＞0.05,χ2=0.15).conclusion eswl should be considered first line therapy for ureteral stone still.stone burden are the main variable of higher re-treatment rate,upper ureteral stone may moving with respiring during eswl.so efficinet shock wave was decreared,re-treatment rate become higher.

目的 评估体外震波碎石治疗输尿管结石的疗效，探讨再治疗率高的原因及输尿管结石的治疗选择。方法回顾2000年1月～2004年12月间eswl治疗输尿管结石的临床资料687例，男455例（66.2%），女232例（33.8%），平均年龄46.6岁（15～83岁）。有双侧输尿管结石6例，单侧多发性输尿管结石12例（4颗1例，3颗2例，2颗9例），共计输尿管结石709颗（含透光结石13颗）。应用上海爱申公司生产的desunit6030型碎石机，c臂x线球管做结石定位。上段输尿管结石（肾盂输尿管交界处至骶髂关节上缘）取仰卧位，下段输尿管结石（骶髂关节上缘下至输尿管口）取俯卧位。为减少eswl引起的肾损伤和疼痛，应用较低的能量，震波发生器电压从9.8～13.2kv，震波频率1.5s。每次治疗设定为1500次震波。治疗后3天摄腹部平片或b超，以后每隔7日重复检查。假如结石未碎或有残留结石最长径＞3mm以上，再次eswl，两次治疗的间隔时间为两周。结石的大小用x线片上的表面积（mm2表示。结果 709颗输尿管结石总的治愈率为97.3%（690颗），再治疗率34.1%（242颗）。其中一次治疗467颗，平均结石大小37.27mm2，治愈464颗（65.4%），3颗改治疗；两次治疗138颗，平均结石大小62.48mm2，治愈131颗（18.5%），7颗改治疗；第1和第2次治疗治愈率（1个月治愈率）为83.8%。3次治疗52颗，平均结石大小79.60mm2，治愈50颗（7.1%），2颗改治疗；4次治疗19颗，平均结石大小101.63mm2，治愈17颗（2.4%），2颗改治疗；5次及5次以上治疗33颗，平均结石大小119.33mm2，治愈28颗（3.9%），5颗改治疗。总计19颗（2.7%）结石改变治疗方式。上段输尿管结石335颗，治愈321颗（95.8%），再治疗129颗（38.5%）。下段输尿管结石374颗，治愈369颗（98.7%），再治疗113颗（30.2%）。经χ2检验，上、下段输尿管结石的再治疗率差异有显著性（χ2=5.40，p＜0.05），治愈率差异无显著性（χ2=0.15，p＞0.05）。不良反应：血压升高13例（1.9%），震波区域疼痛26例（3.8%），震波进入处皮肤点状淤血33例（4.8%），肉眼血尿128例（18.6%），均于第2、3天自行消失。结论 eswl目前仍是输尿管结石的第一线治疗，结石的大小是再治疗率高的主要因素。结石的位置有影响，上段输尿管结石可随呼吸移动，有效震波次数减少，再治疗率比下段输尿管结石高。eswl前注重病例筛选可降低再治疗率。

The increased time resolution of these digitisers will be particularly applicable in systems operating at high frequency, for example 25MHz and above.

这些在时间上的提高将使其能够应用在更高的超声频率下，如25MHz或更高。

These converters are characterized by their large voltage conversion ratio, high output voltage.

它是为满足参量阵声纳的现场使用而研制的，同样适用其他场合变换器有四个特点：变换比大；输出电压高；负载电流大；开关频率高。

However the increase of subscribers asks for more efficient use of the limited spectrum resource. With the development of communication、navigation、radar、mobile communication、programmed telephone and measured instrument devices, the high performance of crystal oscillators is demanded.

随着晶体振荡器在通讯、导航、雷达、移动通讯、程控电话、测量仪表等电子设备中的应用，对晶体振荡器提出了更新、更高的要求，集中表现在频率稳定度高、调频范围宽、线性度优、功耗低、相位噪声低、成本更加低廉等方面。

They weren't aggressive, but I yelled and threw a rock in their direction to get them off the trail and away from me, just in case.

他们没有侵略性，但我大喊，并在他们的方向扔石头让他们过的线索，远离我，以防万一。

In slot 2 in your bag put wrapping paper, quantity does not matter in this case.

在你的书包里槽2把包装纸、数量无关紧要。