查询词典 HF

The foundation of this system provides a good reference to promote the standardization and intelligence of the overhaul and maintenance of vacuum switches. This paper develops a special HF pulse power supply for internal pressure estimation, which achieves the output of HF-HV sinusoidal pulse wave whose frequency and amplitude can be modified respectively, and meets the design requirements according to the results of Simulink simulation and practical experiments. With the help of AT89S52, this paper designs an I~2C serial bus based signal detection system for peak value signal acquisition of HF pulse currents, which communicates with the upper computer by asynchronous serial communication for uploading the data. In the upper computer, a human computer interface is developed by Matlab software, whose functions are to do some computation and graphic display, such as calibrating the relation curve of vacuum degree and peak value of HF pulse currents, vacuum degree computation, and vacuum lifetime evaluation analysis basing on grey forecasting model as well as making relative suggestions.

本文研制了用于真空度检测的高频脉冲电源，通过Simulink仿真和试验检验其满足设计要求，实现了电压幅值和频率独立可调的正弦波高频高压脉冲输出；利用以AT89S52为核心基于I~2C串行总线的信号检测系统实现高频脉冲电流峰值信号的采集，通过异步串行通信实现单片机与计算机之间的数据通信，将检测数据传至上位机；在上位机利用Matlab开发人机交互界面，实现相关数据处理和图形显示，包括真空度——高频脉冲电流峰值关系曲线标定、真空度数值计算、基于灰色预测模型的真空寿命评估分析和提出相应决策建议。

The HF activities in the detail engineering phase are defined as: 'Give input and advice to other departments as required, to ensure that all HF criteria are met… Document implementation of HF by updating HF data sheets prepared in pre-engineering.

HF 活动在细节工程时期中被定义当做： '当做需要把输入和忠告给其他的部门，确定所有的 HF 标准被藉由更新被准备的 HF 数据说明符合 HF 的…文件落实在前。

It is concluded that the ~(176)Hf/~(177)Hf ratios of 91500, Temora and We-1 were homogeneous, because the aforementioned Hf isotopic results consist of at least seven separated performances of aliquots for each zircon sample. These results have significant implications for zircon Hf isotopic determination by using LA-MC-ICPMS.

上述每个结果包括至少7组独立的锆石样晶的溶解、分离和测定，表明标准样91500、Temora和We-1是Hf同位素组成均一的，可作为LAM-MC-ICPMS(激光剥蚀多接受器电感耦合等离子体质谱)的原位微区锆石~(176)Hf／~(177)Hf比值分析过程中外部校正及监控标准样。

Based on hf=λL/DV2/2g,formulain the form of hf= K1·F has beenderived for the hydraulic gradient lines of laterals of subirrigation systems. The formula is also applicable to that of a drip irrigation system. Anotherformula,based on Chezy's V=C RS,in the from of Hf=K2IQ2·F2 has been worked out for the laterals of sprinkler systems.

本文运用管道水动力学原理，对喷灌、滴灌、渗灌系统灌水支管的水力坡降线导出表达的理论公式，讨论其调控的可能途径，为试验研究这类系统的规划设计问题从原理上提供一个分析方法。

It was more appropriate to define the posterior commissure as the posterior margin of HF volumetry, the determination of volume range of HF was helpful in lateralization of temporal lobe epilepsy. 3D MPRAGE was superior to SE in the volumetry of HF.

后连合作为HF体积测定后界较合适，HF正常值的制订有利于颞叶癫痫的定侧。3D MPRAGE序列较SE序列用于HF体积测定更为优越。

At present,Wnt10b is found expression in the developing HF epithelium of the vibrissae and body HF,and it is indicated in the initiated of the HF morphogenesis.

近来研究发现Wnt10b在触须和体毛的胚胎发育过程中表达于毛囊上皮细胞中，可启动并促进毛囊的发育。

Pitch circle diameter: d = mz = 3X12 = 36 Tooth crown heights: ha = m (f0 + x)= 3X (l +0.5)= 4.5 Tooth High: hf = m (f0 + cx)= 3X (l +0.25-0.5)= 2.25 Tooth full height: h = ha + hf = 4.5 +2.25 = 6.75 Addendum circle Chemical pumps diameter: Da = d +2 ha = 36 +2 X4.5 = 45 Fixed string tooth thickness: Sxn = m (π/ 2 * cos2a + xsin2a)= 3X (1.387 +0.6428 X0.5)= 5.125 Fixed string of high gear tooth thickness measurement: hxn = m (π/ 8 * sin2a + xsin2a)= 3X (0.7476X0.117X0.5)= 2.42 Modulus coefficient x0.5 m3 O20 ° pressure angle tooth thickness Sxn5.12 fixed string Addendum Coefficient string f1 fixed gear tooth thickness measurement most high hxn2.42 Teeth z12 2, shaft wear and tear maintenance: Axis gear pump wear is mainly because with the support roller shaft at both ends between the friction and wear, so that smaller shaft diameter.

分度圆直径：d=mz=3X12=36 齿顶高：ha=m（f0+x）=3X（l+0.5）=4.5 齿根高：hf=m（f0+c-x）=3X（l+0.25-0.5）=2.25 齿全高：h=ha+hf=4.5+2.25=6.75 齿顶圆直径：Da=d+2ha=36+2X4.5=45 固定弦齿厚：Sxn=m（π/2*cos2a+xsin2a）=3X（1.387+0.6428X0.5）=5.125 固定弦齿厚测量用齿高：hxn=m（π/8*sin2a+xsin2a）=3X（0.7476X0.117X0.5）=2.42 模数m3变位系数x0.5 齿形角o20°固定弦齿厚Sxn5.12 齿顶高系数f1固定弦齿厚测最齿高hxn2.42 齿数z12 2、轴的磨损维修：齿轮泵中轴的磨损主要是因为轴两端与支撑滚针间的摩擦磨损，使轴径变小。

Using much cheaper Chlorine as fuel, nearly 10 Watt 3.8 micrometer HCl laser was realized by H+Cl2 and H+ClF pump reactions without changing structure of discharge driven HF/DF laser. 12 Watt HF-HCl dual-band lasing were obtained using F-ClF-H2 chain reaction pump system.

以廉价的Cl2为燃料，在不改造电激励HF/DF激光器结构的基础上，分别利用H+Cl2泵浦反应和H+ClF泵浦反应实现了近10W的中心波长3.8μm HCl激光，并利用F-ClF-H2链反应泵浦体系获得了12W的HF-HCl双波段激光。

Well-documented Lu-Hf isotope data from the oceanic basalts show that,the starting area of magma melting for the MORBs derived from the DMM component would be in the the depth of garnet peridotite,i.e.at the depth of 80―90 km instead of less than 60 km,which is at the depth of spinel peridotite as proposed early.The HIMU component,which is characterized by its high rediogenic lead,is refered as a special mantle component differentiated at some time in geological history from the lower mantle.A correlation study of Hf-Nd isotope between the chondrite and oceanic basalts implies that no isolated primitive mantle might have remained.

大量的大洋玄武岩Lu-Hf同位素研究表明：具亏损地幔端元来源的洋中脊玄武岩岩浆部分熔融的初熔区位于石榴石稳定场深度，即深度为80-90 km的石榴石二辉橄榄岩地幔，而不是原来所认为的尖晶石二辉橄榄岩区(深度小于60 km)；以高放射成因Pb为特征的高U地幔端元应代表了下地幔物质在某一特定时期发生分异作用的结果；球粒陨石与大洋玄武岩Hf同位素对比研究表明，没有原始地幔物质能保留至今的迹象。

In frequency domain analysis, we studied the dominant frequency in HF band, LF to HF ratio and the correlation coefficient between simulated and real spectra.

在频域分析上，探讨频谱上高频区主频的频率值、LF与HF的比值以及模拟与真实频谱的相关性比较。

The United Kingdom has pledged to provide technical assistance to the peacekeeping effort in Darfur, including airlifting supplies and equipment to assist the African peacekeepers.

英国承诺为达佛的維和努力提供技术帮助，包括提供非洲的維和部队空运补給和裝备。

Results: The level of ET-1mRNA in placental villus was significantly higher in pre-eclamptic women than that in control group.

结果：妊高征组患者胎盘绒毛组织ET-1 mRNA的表达较正常妊娠组明显增高。