查询词典 sonic velocity

The main research work of this paper are focused on following areas:(1) Based on review of the theory and methods on measurements of particle fields, a new idea for obtaining particle size and velocity distribution within a spray through imaging the particle field with a laser light sheet was put forward;(2) A DPIV (Digital Particle Image Velocimetry) system, is fit for velocity measurements of low speed flows, was developed and expended to particle size distribution measurement;(3) An arithmetic for particle velocity field reconstruction was developed, and the velocity distribution of water mist was also obtained;(4) A software system for particle analysis, which based on image geometry emend, de-noise and image partition was developed, the parameters such as particle size distribution, mean diameter, number of particles, minimum and maximum diameter can be got with this system;(5) A water mist system was developed and its characteristics, such as droplet velocity, size distribution, number of droplets and spray cone angle under different conditions were obtained from experiments with PIVS;(6) The measurement results of water mist characteristics with PIVS were compared and analyzed with the simply simulated results, and in addition, in order to verify the accuracy of PIVS, some experiments were conducted with the standard particles, such as glass-ball with known mean diameter of 50μm and 115μm, metallic coated tracing particle with mean diameter of 12μm;(7) Some experimental studies on interaction of water mist with liquid pool fires were conducted.

本论文的主要工作包括以下几个方面：（1）在对粒子场测量的相关理论和具体方法进行综述分析的基础上，提出了通过采用激光片光对粒子场进行成像以获取其粒径和速度等参数分布的新思路；（2）研制了适宜于低速流动速度场测量的DPIV(Digital Particle Image Velocimetry)系统，并使其实现了对粒子场粒径分布的测量功能；（3）研制了基于粒子运动轨迹的速度场重建算法，获取了细水雾雾场的速度分布；（4）研制了基于几何校正、去噪、图象分割等图象处理方法的"粒度分析软件系统"，该系统既可分析给出粒子场的粒径分布直方图和平均粒径，还可给出粒子的数目以及最大、最小粒径等信息；（5）建立了一细水雾发生系统，并应用上述方法对不同压力条件下细水雾系统的雾场特性（如速度分布、雾滴粒径分布、雾滴的数目、喷雾张角以及雾化长度等）进行了实验测量研究；（6）对细水雾特性参数的PIVS测量结果与计算机简单模拟计算结果进行了定性比较分析，并利用平均粒径为50μm和115μm的玻璃球以及12μm的标准示踪粒子对PIVS系统的粒径和速度测量结果进行了实验验证，同时对其局限性进行了分析讨论；（7）对不同工况条件下细水雾与油池火相互作用的过程进行了模拟实验研究。

Therefore the dispersion curves obtained in the field are primarily consisted of the first mode. For a heterogeneous elastic solid consisting of three homogeneous layers whose interlayer has low velocity, the phase velocity V〓 of the first mode will also close up to the Rayleigh wave velocity of the bottom layer when frequency f→OHz, but V〓 of the first mode will close up to the shear wave velocity of the interlayer when f→∞, and there is a cut-off frequency at high frequency region for the first mode and V〓 close up to the compressional velocity of interlayer when interlayer is liquid.

当三层固体介质中存在软夹层时，若f→OHz，则其基阶模式的相速度V〓→V〓（V〓为最底层介质的瑞利波速度）；若f→∞，其基阶模式V〓→V〓（V〓为中间层介质的横波速度）；若三层介质中存在液体夹层，当f→OHz时，基阶模式V〓→V〓，而基阶模式在高频段存在一个截止频率，截止频率处的瑞利波速度V〓→V〓；由此可判定，野外实测的相速度频散曲线不仅有基阶导波模式，同时还应有高阶导波模式波的存在，接收信号中存在模式间的跳跃，因此频散曲线会产生"之"字形现象。

Results show that floes' VC and D at the surface water were closely related to current velocity; and the peaks of VC lag those of the current velocity. The lag variation during ebb and flood tides is 10-30min and 30-50 min, respectively. Current velocity at 50 cm/s is a turning point of D vs. vertical average current velocity, before the point, Dm increases with current velocity, and decreases after the point. Similarly, VC at 75μl/L becomes a critical point in the surface water, below the point, D increases with VC, and above the point, D stabilizes.Δp is D dependent, larger floes have much lower Δp than smaller floes. Both D and Δp of floes affect ω. In the surface water during spring tide and neap tide, a power exponent relationship exists between Δp and D, and ω and D.

研究表明：①长江口徐六泾表层絮凝体体积浓度主要受水流流速影响，再悬浮现象明显，体积浓度过程线滞后流速过程线，落潮期间滞后10-30min，涨潮则滞后30-50min；②小于一定流速时絮凝体平均粒径随流速增大而增大，大于一定流速时絮凝体平均粒径则随流速增大而减小，徐六泾夫、小潮表层絮凝体在50cm/s的垂线平均流速时出现平均粒径与垂线平均流速关系的转折；③徐六注大、小潮表层絮凝体平均粒径在体积浓度75μl/L时出现平均粒径与体积浓度关系的转折，体积浓度小于75μl/L时粒径随体积浓度增加而增大，超过75μl/L时粒径随体积浓度的增加变化不明显；④絮凝体有效密度由粒径大小控制，粒径大，有效密度小，反之亦然，粒径和有效密度共同决定絮凝体静水沉速，有效密度和沉速与平均粒径之间均存在良好的幂指数关系。

It was suggested that aging did not only influence diastolic filling period, but also influence STI. 3. With increasing age, whether at rest or during exercice, fractional shortening of minor semiaxis, mean velocity of circumferential fiber shortening, cardiac index and ejection fraction did not change, but immediately post pacing, PEP prolonged and PEP/ LVET increased in elderly group and did not change in young group. It was suggested that STI was sensitivity in detecting systolic function of LV. 4. There was a good correlation between aging and decreased compliance and diastolic function of left ventricle which was manifested by a reduction of early diastolic peak folw velocity, time-velocity integral of early diastole, 1/3 filling fraction (1/3FF)(r=-0.958,-0.875 and -0.937, P＜0.01～0.001) and a significant compansatory increase in peak flow velocity of atrial contraction, time-velocity integral of atrial contraction, the ratio between APFV and EPFV and the ratio of ATVI and Total TVI (r=0.958, 0.956, 0.966 and 0.986, P＜0.001) and the prolongation of Dec T and RFP with increasing age. It was particularly true for the subgroups above the age of 50 years.

静息状态下收缩时间间期与年龄无相关性，负荷后即刻，老年组射血前期延长(P＜0.05)，射血前期与射血期比值加大(P＜0.05)，青年组无变化，提示年龄因素亦影响STI，但由于静息状态下得到代偿，STI变化往往表现不明显。3、静息及负荷状态左室短轴缩短率、平均周径缩短率、心指数及射血分数均不随年龄增长而变化，而负荷后即刻老年组PEF延长，PEP/LVET加大，提示STI是检测左室收缩功能的敏感指标。4、随年龄增长，心房收缩期充盈峰值流速、流速积分、充盈分数及心房收缩期与舒张早期充盈峰值流速之比值显著增高(r＝0.958、0.956、0.986及0.966，P均＜0.001)，舒张早期充盈峰值流速及流速积分、1/3充盈分数(1/3FF)下降(r＝-0.958、-0.875及-0.937，P＜0.01～0.001)。

The tidal river discharge observing system of this thesis gives a new method and experience of the hydrology observing to the river reach and cross section with complicated landform and flow, or busy shipping. This system has achieved 3 innovations: instruments for measurements which use the unmechanized rotor and continue measuring ADCP as the velocity mainframe; methods of velocity measurement which change the vertical velocity measurement to horizontal velocity measurement; the tidal discharge measurement which solve the problem that current method of discharge measurement can not achieve the accuracy of the criterion according to the continuous real time observing over the velocity of flow.

本论文研究的感潮河流流量监测系统，具有测验设备的创新，用可连续测验的非机械转子式的声学多普勒流速剖面仪为测速主机；流速测验方式的创新，改变以往测取垂向流速为水平流速的方式；潮流量测验方式的创新，对流速进行连续实时的监测，解决了用现行测流方法达不到规范要求精度的问题；为地形、水流复杂或是航运频繁的测验河段和断面，提供水文监测的新方法、方式和经验。

In order to probe the relationships between wave equation offset domain common image gathers/angle domain common image gathers with migration velocity, we quantitatively derive the changes of ODCIGs and ADCIGs along with migration velocity on the assumption of uniform velocity medium with a horizontal reflector. We come to conclusion that ODCIGs are hyperbolas with half offset; on the contrary, they are ellipses. Combined with the results of depth focusing analysis, we find the apparent incident angles in ADCIGs are larger than the real incident angles when the migration velocity is larger than the true one and vice versa. With lower migration velocity, the residual moveout on ADCIGs is an ellipse with the tangent of apparent incident angle; otherwise, it's a hyperbola.

为了得到波动方程偏移距域共成像点道集和角度域共成像点道集与偏移速度的关系，在匀速单层水平反射情况下，对ODCIGs和ADCIGs随偏移速度的变化进行了定量的推导，得到偏移速度偏小时ODCIGs与半偏移距成双曲关系，反之成椭圆关系；结合深度聚焦分析，得到偏移速度偏大时ADCIGs中视入射角大于真入射角，反之，小于真入射角；在速度偏小时，ADCIGs上剩余时差与视入射角的正切值成椭圆关系，反之成双曲关系。

When gas superficial velocity was about equal to liquid superficial velocity, the probability density function of liquid holdup had a twin-peaked, when liquid superficial velocity was constant, one of the peaks would fade out and disappear with the in crease of gas superficial velocity. Through using the characteristics, the relative size of gas and liquid superficial velocity can be set initially.

在段塞流动中，当气相折算速度和液相折算速度相差不大时，持液率概率密度函数呈双峰分布；当液相折算速度不变时，随着气相折算速度的增大，持液率概率密度函数第2峰值逐渐减小，直至消失而变为单峰分布；利用这一特征可初步确定段塞流动中气、液相流量相对大小。

Centralized by discussing the sonic showing manner of music work, the article uses the experience from ethnomusicology applying it to face the real sound directly, and taking Mozart抯 Piano Sonata K330 as an example to do a thorough comparison between the sonic showing manners of Vladimir Horowits, Glenn Gould, Claudio Arrau, Ingrid Haebler and Andras Schiff according to their performance recordings.

本文以音乐作品的音响呈现方式为论述中心，借鉴民族音乐学直接面对具体音乐事象的研究方法，直接面对实际发声的音响，以莫扎特第十首钢琴奏鸣曲（K330）为个案，通过霍洛维兹、古尔德、阿劳、黑布勒、希夫的演奏录音对他们的音响呈现方式进行全方位的比较。

Sonic Chime: Once per day, a knell beetle can emit a cone of sonic energy from the chitinous bell above its head.

音波谐鸣：每天1次，丧钟甲虫可以从头上的几丁质钟形结构中放射出一束锥形的音波能量。

Urban Palimpsest is a meditative inquiry into the connection between urban spaces and our collective sonic imagination, an exercise in distrusting the ears, and a momentary disruption of sonic judgement.

Urban Palimpsest》让我们反思城市空间跟集体声音想像之间的联系，教人质疑自己的耳朵，并暂时推翻一切有关声音的判断。

Finally it offers the analysis of the fault-tolerance system as well as its test verification.

这样，运行于空间环境中的系统的设计目标就是在保证系统实时性

However, it is still difficult to find out the real reason of the increase of the keratinized gingiva during the orthodontic extrusion whether it is due to the proliferation of the gingival tissue or to its elastic nature, that is because the proliferation of the fibroblasts as well as the connective tissue changes in volume and the intra-fibers spaces were all immeasurable in most of the studies.

然而，仍然难以找到真正的原因增加的角化牙龈在正畸挤压它是否是由于扩散的牙龈组织或其弹性性质，这是因为增殖的成纤维细胞以及作为结缔组织的变化量和内部纤维空格都是不可估量的，大多数的研究。