Relationship between Star-Wave Test and Visual/Motor Maturity in Young Children

The developmental maturity (M) scale using the Star-Wave Test that was independently developed by Yalon and Zion indicates poor learning abilities if the M-scale score is low, which may be caused by developmental delays, such as intellectual disability and learning disorder or organic mental disorder. Furthermore, the distress (D) scale is thought to be influenced by mild neurological disorders, hand coordination problems, and environmental factors. In this study, we conducted a Star-Wave Test on 44 nursery school children in Japan and examined the M scale, the D scale, as well as the level of stress induced by coordination problems and the environment. The t-test was conducted on the M scale and D scale of the group without coordination problems and that with coordination problems, and we found a significant difference at 1% level. From this result, we can confirm the relationship of the M scale and the D scale with Visual and motor maturity.

Detection of internal crack growth in polyethylene pipe using guided wave ultrasonic testing

Despite the success of guided wave ultrasonic inspection for internal defect detection in steel pipes,its application on polyethylene(PE)pipe remains relatively unexplored.The growth of internal cracks in PE pipe severely affects its pressure-holding capacity,hence the early detection of internal cracks is crucial for effective pipeline maintenance strategies.This study extends the scope of guided wave-based ultrasonic testing to detect the growth of internal cracks in a natural gas distribution PE pipe.Laboratory experiments and a finite element model were planned to study the wave-crack interaction at different stages of axially oriented internal crack growth with a piezoceramic transducer-based setup arranged in a pitch-catch configuration.Mode dispersion analysis supplemented with preliminary experiments was performed to isolate the optimal inspection frequency,leading to the selection of the T(0,1)mode at 50-kHz for the investigation.A transmission index based on the energy of the T(0,1)mode was developed to trace the extent of simulated crack growth.The findings revealed an inverse linear correlation between the transmission index and the crack depth for crack growth beyond 20%crack depth.

RESEARCH ON MICROWAVE HUMIDITY TESTING OF CERAMIC PRODUCTS

This paper analyses the principle of microwave humidity testing. According to the problems in the production procedure of ceramic products, a microwave humidity testing system is designed and analyzed for its advantages. Furthermore, the system has been applied to the production line that produces ceramic products and the testing results are also satisfying.

Numerical Simulations and Model Tests of the Mooring Characteristic of A Tension Leg Platform Under Random Waves

Analyzing the dynamic response and calculating the tendon tension of the mooring system are necessary for the structural design of a tension leg platform （TLP）. The six-degree-of-freedom dynamic coupling responses and the mooring characteristics of TLP under random waves are studied by using a self-developed program. Results are verified by the 1：40 scaling factor model test conducted in the State Key Laboratory of Ocean Engineering at Shanghai JiaoTong University. The mean, range, and standard deviation of the numerical simulation and model test are compared. The influences of different sea states and wave approach angles on the dynamic response and tendon tension of the mooring system are investigated. The acceleration in the center and corner of the deck is forecasted.

Model Test and Design of the Wave Energy System on "Central Fairway No. 1" Light Ship

This paper presents the test of a ship model for the design of a backward-bent duct oscillating water column type wave energy conversion system, to supply electric power for a light ship. This system suggests a new way to produce electric power automatically for large light ships.

Wave Motion Compensation Scheme and Its Model Tests for the Salvage of An Ancient Sunken Boat

The application of the vertical hoisting jack and wave motion compensation techniques to the salvage of an ancient sunken boat is introduced. The boat is wooden, loaded with cultural relics. It has been immersed at the bottom of the South China Sea for more than 800 years. In order to protect the structure of the boat and the cultural relics inside to the largest extent, an open caisson is used to hold the sunken beat and the silts around before they are raised from the seabed all together as a whole. In the paper, first, the seakeeping model test of the system of the salvage barge and the open caisson is done to determine some important wave response parameters. And then a further experimental study of the ap- plication of the vertical hoisting jack and wave motion compensation scheme to the salvage of the sunken boat is carried out. In the model tests, the techniques of the integrative mechanic-electronic-hydraulic control, wave motion forecast and wave motion compensation are used to minimize the heave motion of the open caisson. The results of the model tests show that the heave motion of the open caisson can be reduced effectively by the use of the present method.

Excitation and Detection of Shear Horizontal Waves with Electromagnetic Acoustic Transducers for Nondestructive Testing of Plates

The fundamental shear horizontal（SH0） wave has several unique features that are attractive for long-range nondestructive testing（NDT）. By a careful design of the geometric configuration, electromagnetic acoustic transducers（EMATs） have the capability to generate a wide range of guided wave modes, such as Lamb waves and shear-horizontal（SH） waves in plates. However, the performance of EMATs is influenced by their parameters. To evaluate the performance of periodic permanent magnet（PPM） EMATs, a distributed-line-source model is developed to calculate the angular acoustic field cross-section in the far-field. Numerical analysis is conducted to investigate the performance of such EMATs with different geometric parameters, such as period and number of magnet arrays, and inner and outer coil widths. Such parameters have a great influence on the directivity of the generated SH0 waves that arises mainly in the amplitude and width of both main and side lobes. According to the numerical analysis, these parameters are optimized to obtain better directivity. Optimized PPM EMATs are designed and used for NDT of strip plates. Experimental results show that the lateral boundary of the strip plate has no perceivable influence on SHO-wave propagation, thus validating their used in NDT. The proposed model predicts the radiation pattern ofPPM EMATs, and can be used for their parameter optimization.

Laboratory Research on Effective Test Area of Short-Crested Waves Generated by Two-Sided Segmented Wavemakers

The size and shape of the effective test area are crucial to consider when short-crested waves are created by segmented wavemakers. The range of the effective test area of short-crested waves simulated by two-sided segmented wavemakers is analyzed in this paper. The experimental investigation on the wave field distribution of short-crested waves generated by two-sided segmented wavemakers is conducted by using an array of wave gauges. Wave spectra and directional spreading function are analyzed and the results show that when the main direction is at a certain angle with the normal line of wave generators, the wave field of 3D short-crested waves generated by two-sided segmented wavemakers has good spatial uniformity within the model test area. The effective test area can provide good wave environments for seakeeping model tests of various ocean engineering structures in the deep ocean engineering basin.

Non-Contact Stress Measurement during Tensile Testing Using an Emat for SH₀-Plate Wave and Lamb Wave

The stress on a test specimen during tensile testing is generally measured by a strain gauge. This method has some problems in that it would influence the measurement conditions of the tensile test and can evaluate only the position at which the strain gauge is attached. The acoustoelastic method is proposed as a method replacing the strain gauge method. However, an ultrasonic sensor with a piezoelectric oscillator requires a coupling medium to inject an ultrasonic wave into a solid material. This condition, due to the error factor of the stress measurement, makes it difficult for the ultrasonic sensor to move on the specimen. We then tried to develop a non-contact stress measurement system during tensile testing using an electromagnetic acoustic transducer (EMAT) with an SH0-plate wave and S0-Lamb wave. The EMAT can measure the propagation time in which the ultrasonic wave travels between a receiver and a transmitter without a coupling medium during the tensile testing and can move easily. The interval between the transmitter and the receiver is 10mm and can be moved along the parallel direction or the vertical direction of the tensile load. The transit time was measured by a cross-correlation method and converted into the stress on the test specimen using the acoustoelastic method. We confirmed that the stress measurement using an SH0-plate wave was superior to that with an S0-Lamb wave.

Test particle simulations of resonant interactions between energetic electrons and discrete, multi-frequency artificial whistler waves in the plasmasphere

Modulated high frequency （HF） heating of the ionosphere provides a feasible means of artificially generating ex- tremely low frequency （ELF）/very low frequency （VLF） whistler waves, which can leak into the inner magnetosphere and contribute to resonant interactions with high energy electrons. Combining the ray tracing method and test particle simulations, we evaluate the effects of energetic electron resonant scattering driven by the discrete, multi-frequency arti- ficially generated ELF/VLF waves. The simulation results indicate a stochastic behavior of electrons and a linear profile of pitch angle and kinetic energy variations averaged over all test electrons. These features are similar to those associated with single-frequency waves. The computed local diffusion coefficients show that, although the momentum diffusion of relativistic electrons due to artificial ELF/VLF whistlers with a nominal amplitude of ~ 1 pT is minor, the pitch angle scattering can be notably efficient at low pitch angles near the loss cone, which supports the feasibility of artificial triggering of multi-frequency ELF/VLF whistler waves for the removal of high energy electrons from the magnetosphere. We also investigate the dependences of diffusion coefficients on the frequency interval （△f） of the discrete, multi-frequency waves. We find that there is a threshold value of Af for which the net diffusion coefficient of multi-frequency whistlers is inversely proportional to △f （proportional to the frequency components Nw） when △f is below the threshold value but it remains unchanged with increasing Af when △f is larger than the threshold value. This is explained as being due to the fact that the resonant scattering effect of broadband waves is the sum of the effects of each frequency in the ＇effective frequency band＇. Our results suggest that the modulation frequency of HF heating of the ionosphere can be appropriately selected with reasonable frequency intervals so that better performance of controlled precipitation of high energy electrons in the plasmasphere by artificial ELF/VLF whistler waves can be achieved.

Three-Dimensional Model Test for Port Engineering with Multi-Directional Waves

-The necessity of using irregular waves, especially multi- directional waves to conduct three-dimensional model tests for port engineering and the test method are described in this paper through an example of model test for a port. The test results show that a deep navigation channel has a large effect on the waves in front of the breakwater near the port entrance and on the wave condition in the port.

Evaluation of Treadmill Exercise Test Induced U-wave Inversion in Diagnosis of Coronary Artery Disease

U-wave changes during treadmill exercise test were compared between 34 patientswith CAD and 33 normal controls.All of them were confirmed by coronary angiographv.Tenpatients with CAD and 1 normal subject in this study showed U-wave inversion during exercisetest.Of the 10 patients,4 had significant stenosis in one-vessel and 6 in multi-vessel of the ma-jor coronary arteries.The sensitivity,specificity and predictive value of exercise-inducedU-wave inversion were 29％, 97％ and 91％,respectively.It is proposed that exercise inducedU-wave inversion is a reliable predictive index of CAD.

Modeling of Electromagnetic Wave Propagation and Its Applicationin Virtual Test

With the development of virtual test,the computation of the effect of different weather conditions on electromagnetic wave propagation is required in many simulation systems. Firstly,this paper presents a unique point of view for computing the electromagnetic wave attenuation ratio under different weather conditions by means of an independent electromagnetic wave propagation component that can be directly implemented in virtual test, and is easy to configure and easy to reuse. We present an analysis of the principles of electromagnetic wave propagation and the algorithms designed for realization of various propagation models within the electromagnetic wave propagation component. Secondly,this paper presents a use-case analysis and outlines the design of the component,verifies the developed models under various weather conditions,and obtains equivalent values as those obtained theoretically. Finally,we build a virtual test system,verify the system in different weather conditions,and again obtain equivalent values to those obtained theoretically. The algorithms in the electromagnetic wave propagation component are developed in the C language, which substantially improves the computational speed,and meets the real-time requirements of the virtual testing platform.

青藏高原东坡地形对影响云南降水的高原涡的作用机理

利用常规观测资料、FNL分析资料及经质控后的自动站小时降水数据,诊断分析了青藏高原东坡地形在2017年7月2-3日高原涡影响云南降水过程中的作用,并利用数值模式WRFv4.0对此次过程进行了地形敏感性试验。结果表明:高原涡是此次云南强降水的重要影响系统;低涡中心及附近区域中高层维持暖心结构,并呈现显著的上升、下沉运动交替的分布;过程累积雨量分布表现为两条明显的与山脉走向平行的西北-东南向雨带,且具有强弱交错的分布特征,强降水集中出现在午后至傍晚及前半夜两个时段内,中心均位于地形边坡,并随着低涡向下游传播;南亚高压、西北辐散气流、西太平洋副热带高压及滇缅高压为低涡的东移发展提供了有利的高空环流场,500 hPa正涡度及700 hPa水汽通量辐合中心对强降水落区具有较好指示意义;低涡降水期间存在β中尺度重力波,波动由青藏高原东坡地形激发,沿着300~200 hPa的气层传播,高空的非地转平衡运动及垂直风切变为重力波的发展及传播提供了有利条件,重力波先于低涡及降水向下游方向移动及发展,波脊处对应上升运动及辐散中心,波槽处对应下沉运动及辐合中心,强降水及波脊均位于低涡西南侧强辐合上升运动区;地形高度降低后,其机械阻挡抬升作用减弱,重力波和高原低涡消失,雨带强度及空间分布特征发生显著改变。高原东坡地形对高原涡的形成和发展,以及高原涡影响下的云南降水具有重要作用。

海洋生物柔性拦截网波浪力特性

取水明渠柔性拦截网受波浪作用上下运动,有限振幅波理论中的水质点位置难以确定,导致波浪力计算存在困难。基于水池试验方法对波浪力形成的速度理论计算方法进行修正。结果表明,波浪力水质点位置与波高以及波周期相关,修正公式计算值与试验结果误差小于20%,符合性较好。研究成果对于拦截网的承载力设计和运行监测具有一定的指导作用。

时速120 km地铁快线空气动力学试验研究

为探明设计时速120 km快速地铁列车在多区段桥隧衔接线路运行时的气动效应和气密性能,采用实车试验的方法,在武汉某多区段桥隧衔接地铁快线对某4车编组的新研A型密封性地铁列车开展空气动力学测试。实验测试系统采用LL-250-15A型Kulite压力传感器,通过测量列车外部和内部的瞬态压力变化,分析全线路车外压力波动特性,对比沿列车长度方向不同测点位置的压力变化幅值,并分析不同空调状态下的车内压力舒适性。经过3次实验测试分析,该实验的结果具有可重复性。研究结果表明:全线路运行时,列车在隧道段内加减速导致车外压力变化幅值明显大于高架段,气动效应最恶劣的位置为地下段人防门变截面处,列车上行通过该处时车外任意3 s内压力变化幅值为1 071 Pa,下行通过该处时车外任意3 s内压力变化幅值为905 Pa;相对于下行线全线路,上行线车外任意3 s内压力变化幅值大18.3%;列车正线运营时压力波保护阀会在压力变化剧烈区段进行动作响应,列车上行时,空调开启、压力波保护阀正常启用状态下,车内任意3 s内压力变化幅值相对于压力波保护阀打开未启用时减少了16%,下行时,减少了28%,空调压力波保护阀能够有效降低车外压力波动对车内气压变化的影响。本文研究成果可为快速地铁线路设计、地铁列车运营及地铁气密性优化提供参考依据。

Comparison of Vs and SPT Soil Liquefaction Assessments of NCEER: Including Hypothesis Testing

Soil liquefaction is one of the complex research topics in geotechnical engineering and engineering geology. Especially after the 1964 Niigata earthquake (Japan) induced many soil liquefaction incidents, a variety of soil liquefaction studies were conducted and reported, including the liquefaction potential assessment methods utilizing the shear wave velocity (Vs) or SPT-N profiles (SPT: standard penetration test). This study used the Vs and SPT methods recommended by the National Center for Earthquake Engineering Research (NCEER) to examine which is more conservative according to the assessment results on 41 liquefiable soil layers at sites in two major cities in Taiwan. Statistical hypothesis testing was used to make the analysis more quantitative and objective. Based on three sets of hypothesis tests, it shows that the hypothesis—the SPT method is more conservative than the Vs method—was not rejected on a 5% level of significance.

基于海尔贝克式排布的电磁铁EMAT研制

电磁声传感器由于其结构简单且无需耦合等特点,在超声无损检测领域具备显著的应用潜力。传统的永磁铁式横波电磁声传感器存在诸多缺陷,包括换能效率低、激发超声模态不具一致性,以及在铁磁性试件上检测时吸附力强、难以移动等,这些问题不仅影响了检测结果的准确性,也限制了其应用范围。本研究基于永磁铁海尔贝克式电磁声传感器以及空芯电磁铁电磁声传感器的特点,研制了一种新型的电磁铁横波传感器,实现单侧磁场增强的同时,可实现偏置磁场强度可调。本文采用正交试验的方法对传感器励磁磁铁以及涡流线圈结构参数进行优化,提高了回波信号的幅值。研究结果表明,经过优化后的电磁声传感器对于铝板的检测,可显著增加试件表面产生的垂直磁场强度及分布范围,并大幅降低水平磁场,能够更有效地激发较为纯净的横波。

基于预测兰姆波参考信号的缺陷概率成像

针对兰姆波缺陷概率成像需要从材质相同的无缺陷结构获得参考信号的问题,提出一种基于参考信号理论预测的概率成像方法,实现兰姆波缺陷定位.该方法将初始信号和兰姆波的频散特性结合,根据拟合得到的幅值衰减系数计算概率成像路径上的参考信号.根据该方法计算得到的参考信号和对应路径上响应信号的希尔伯特谱定义缺陷表征指数,结合兰姆波椭圆概率成像方法实现缺陷定位.单一缺陷和双缺陷成像定位的实验结果表明,该方法可以得到缺陷的概率图像,对缺陷定位的误差小于7.07 mm,解决了需要测量兰姆波参考信号的问题,定位准确、实用性好.

基于串并行双分支网络的冲击波信号重构方法

通过有限测点数据重建冲击波场内压力分布、通过残缺数据重构完整的冲击波压力曲线,对武器威力以及目标毁伤评估具有重要价值。针对爆炸冲击波信号重构问题,建立Res-GRU分支以串行方式捕捉冲击波超压信号局部时序依赖关系;建立Transformer分支以并行方式分析信号全局潜在特征;建立特征融合单元进行高阶特征融合,实现不同阶段信息逐层互补;进而构建了基于门控循环单元(gated recurrent unit,GRU)和Transformer模型的串并行双分支网络(G-TNet)。试验研究表明:G-TNet综合考量了信号的时序关系、数据变化规律等特征信息;在基于有限测点数据的冲击波场压力分布重构试验中,重建的模拟、实测超压数据与原始值之间均方误差(mean square error,MSE)分别为5.0×10^(-6)、1.2×10-3,平均峰值误差分别为0.49%、27.01%,平均正压时间误差分别为15.62%、15.91%,平均比冲量误差分别为17.66%、19.33%;在基于残缺数据的冲击波压力曲线重构试验中,重构的模拟、实测信号的缺失值与原始值之间MSE分别为5.0×10^(-6)和5.0×10^(-4),平均绝对误差(mean absolute error,MAE)分别为0.0010和0.0171;G-TNet重构结果优于主流方法,满足爆炸冲击波压力重构指标要求。