Publications

Robust 3D vessel trajectory monitoring with monocular vision based deep learning and surveillance cameras

Fast M2 estimation for fiber beams through deep learning

New Progress in Polymeric Electret Materials

Time-Frequency Characteristics of Parachute Gun Shockwave Based on VMD-HT

During the ejection process of the fighter pilot, the parachute is shot out by the life-saving seat gun, which generates a shockwave that endangers human safety. In order to accurately and stably extract the time-frequency distribution characteristics, the shockwave signal is obtained through parachute gun shooting experiments, and features of the shockwave signal is extracted by using Variational mode decomposition and Hilbert transform methods (VMD-HT). VMD is a high sampling rate shockwave signal decomposition technique, which is suitable for analysing unsteady airborne parachute gun shooting shockwave signals. The HT method is used to accurately extract the relationship between time, instantaneous frequency and energy for the decomposed signal, and to obtain the marginal spectra. The analytic results show that the shockwave signal lasting 3ms has a significant energy concentration in the low frequency band of 0∽1kHz, which is important for the better protection of pilots.

A differentiation based method to transmission network planning for improving anti-disaster ability

Frequent occurrences of meteorological disasters (MD) in recent years have revealed the deficiencies of traditional transmission network planning (TNP) methods, which fail to establish mathematical relationship between the MD and the transmission line outage rate (TLOR) when calculating the vulnerability index of transmission network. As a result, the planning schemes are usually unable to determine the critical lines that should be guaranteed in the event of MDs, which is against the basic principles of economy and reliability. In this paper, a differentiation based method to TNP is proposed to optimize the fortification standard levels of different transmission lines for improving the anti-disaster ability. A three-state meteorological model is firstly developed to evaluate the effect of MD on TLOR; then a multi-objective TNP model is built considering economy and vulnerability objectives. Results show the TNP method can determine the fortification standard level of each transmission line for improving the anti-disaster ability while minimize the construction cost as much as possible, which is of significant reference value to the TNP under the meteorological disaster-prone environment.

Study on Heart Shaped Buckling Mechanism and Prevention Method of Thin Silicon Steel

摘要: 为改善薄带硅钢卸卷后出现的心形屈曲缺陷,建立计及层间摩擦力和料卷各向异性的无芯筒工况收卷-卸卷内应力模型。硅钢表面存在涂层,故进行压缩板叠试验得到0.23 mm硅钢径向模量公式。基于压力埋管理论分析料卷心形屈曲机理,并计算了屈曲层数,计算值与现场26组测量值相吻合,验证了理论的正确性。系统分析助卷张力、助卷层数和稳定张力对屈曲层数的影响。研究表明,屈曲层数随助卷张力增加先减小后增加,助卷张力为30MPa时屈曲层数最少,仅35层;助卷张力与稳定张力之差较大时,层间应力差迅速下降,之后由下降转为上升,最后趋于稳定;助卷层数从10层增加到70层,屈曲层数仅减少7层;稳定张力对屈曲层数影响最显著,稳定张力从26 MPa减小到14 MPa屈曲层数减少40层。

Data augmentation of dynamic responses for structural health monitoring using denoising diffusion probabilistic models

A Short Primer on Quantum Mechanics

A summary is not available for this content so a preview has been provided. Please use the Get access link above for information on how to access this content.

Substructure damage identification based on response reconstruction in frequency domain and model updating

Optimisation of the Azadegan oilfield wellbore lost circulation diagnosis model: A hybrid model combining the SIKPW denoising framework and SSA optimisation

Measurement of wireless pressure sensors fabricated in high temperature co-fired ceramic MEMS technology

High temperature co-fired ceramics (HTCCs) have wide applications with stable mechanical properties, but they have not yet been used to fabricate sensors. By introducing the wireless telemetric sensor system and ceramic structure embedding a pressure-deformable cavity, the designed sensors made from HTCC materials (zirconia and 96% alumina) are fabricated, and their capacities for the pressure measurement are tested using a wireless interrogation method. Using the fabricated sensor, a study is conducted to measure the atmospheric pressure in a sealed vessel. The experimental sensitivity of the device is 2 Hz/Pa of zirconia and 1.08 Hz/Pa of alumina below 0.5 MPa with a readout distance of 2.5 cm. The described sensor technology can be applied for monitoring of atmospheric pressure to evaluate important component parameters in harsh environments.

DIMMC: A 3D vision approach for structural displacement measurement using a moving camera

A Strange Portrait: Map of the World in Korea

A New Failure Mechanism of Inter Layer Dielectric Crack

Converting gold wire to copper wire for IC packaging is a big trend recently which has both advantage and disadvantage. Cu wire is good for packaging cost saving to current semiconductor industry, but it may also create quality and reliability issues. Since Cu is much harder and stiffer material than Au, it may require a greater force and USG power to insure good bonding to pad, and a larger bond force and USG power in turn increases the risk of ILD crack during the bonding process. The wafer tech in this study is CMOS40nm, Al thickness is 28KA, with 53um pad opening. The ILD crack mechanism which is discussed in this paper is different. The failure mode during ATE test is leakage failure. After de-cap and cratering test, there is no cratering/damage on failed pad under microscope check. FIB was performed on failed pad and confirmed the damage between Metal 2 and Metal 3, and no damage on top metal. The link between IV curve trace and ILD crack was studied. The root cause of the ILD crack was studied, material and machine variation were also take into consideration. Parameter optimization DOE was done. Key wire bond parameters include the initial force, USG power etc. The wire pull, ball shear, IMC, Al remnant etc. are key response. The result shows that lower USG and higher initial force can get better wire bond performance. The die was packaged into a MAPBGA package. Electrical test was performed on the assembled parts at T0, post MSL3/260degree C, post 264h UHST (110°C/85%RH), and post TC700cycles (-55°C to 150°C). All units post stress clean passed without any failure. The overall leakage failure rate at ATE test is reduced.

Using polynomial chaos expansion for uncertainty and sensitivity analysis of bridge structures

Affecting factor of transparency of translucent soap and control of procedure in production

This article describes the factors which affect the transparency in grinding process of translucent soap production from designing the formula to controlling the parameter of process, to packetting and storning the product etc, esp emphasise the relation between FA content (w %) of the soap-drops, melting point of the formula, temperature of the process and transparency, then discuss the effect of other relative factors for transparency of product, including refined-grind, plodder, water-chilled, cooling-soap, soaps shape, package and storage, etc moreover, give the relative parameter of the process control and the method controlling these factors

Research on application of wavelet analysis in signal processing of extremely low frequency magnetic targets

Based on the measured signals of extremely low frequency underwater magnetic targets, this paper extracts the magnetic anomaly data of sensors at 50Hz for denoising processing, and uses the denoised magnetic anomaly data as the basic data. Random noise is added to the basic data as a simulated noise signal. Based on Stein's unbiased likelihood estimation threshold method, two wavelet family Symlets, Daubechie and soft and hard threshold selection methods commonly used in denoising literature are used to denoise the measured underwater magnetic target signal data. The different de-noising results are calculated and compared. The de-noising signal-to-noise ratio of the data is used as the evaluation index, and the de-noising effect and reliability of different combined methods are objectively analyzed. Research shows that the hard-thresholding of sym7 as the generating wave function has the lowest signal-to-noise ratio and poor denoising effect. The soft threshold processing using db9 as the generating wave function has the highest signal-to-noise ratio, which can achieve the best denoising effect.

Assessment of Physical Activity Level, Health Status and Perceptual Impairment in Adolescent Students