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A novel time domain method is proposed to estimate the time-varying statistics of nonstationary random pressure load from structural strain response samples. Orthogonal polynomials and Karhunen–Loève expansion are adopted to represent the spatial distribution of the stochastic pressure load and the random structural strain data, respectively, which transform the random pressure load identification problem to a problem of estimating a few deterministic time-varying coefficients. Numerical simulation on a plate structure subjected to nonstationary random fluctuating load is conducted to validate the proposed method, and the influence of the load's correlation length on the identification accuracy is also discussed. To show the application perspective of the proposed method, the nonstationary gust-induced random pressure load on a wing structure is reconstructed from structural strain data. Some practical aspects, such as the number of response samples, the level of noise in the strain response, the order of orthogonal polynomial used, and the regularization method used, on the performance of the load identification method are also discussed. [ABSTRACT FROM AUTHOR]

In order to obtain the full spectrum information of the sample, improve the resolution and sensitivity, and save materials and reagents, an upgraded CCD-1 photoelectric direct reading emission spectrometer was adopted, and the mixture of potassium pyrosulfate, sodium fluoride, alumina, carbon and germanium dioxide was used as the spectrum buffer. When the ratio of the sample to the spectrum buffer was 1 : 1, it was evenly mixed and compacted in the lower electrode, and the problem of sampling was solved by opening a side hole in the lower electrode. At the same time, the selection of upper electrode specifications was investigated, the excitation current and exposure time were optimized, and an analytical method for the determination of trace silver, boron and tin in geochemical samples by solid sampling-CCD photoelectric direct reading emission spectrometry was established. The results showed that the excitation current wass 5 A for 3 s in the pre-combustion stage, and 14 A for 35 s in the excitation stage. The interference spectrum could be corrected accurately, the background was deducted automatically, and the baseline fluctuation of the sample was observed in real time. The calibration curve was drawn by using synthetic silicate reference materials for spectral analysis. The detection limits (3S) of silver, boron and tin in the six national first-class reference materials were 0. 01, 0. 55 and 0. 12 mg/kg respectively, and the relative standard deviations (w=12) were 2. 4%--8. 7%, 5. 8%--9. 4%, and 5. 2%--8. 7% respectively. The measured values were consistent with the standard values, and all the indexes of the method met the requirements of "Quality Management Standard for Laboratory Testing of Geology and Mineral Resources" (DZ/T 0130.4--2006). [ABSTRACT FROM AUTHOR]

An identification method for annularly distributed random dynamic load was proposed to estimate the non-uniform random base excitation at the connection ring between a satellite and a rocket. Firstly, B-spline functions were adopted to represent the load distribution function. The distributed random excitation model based on B-spline functions was established. The distributed load identification problem was converted into a coefficient-estimation problem. Then, the relational expressions between the response and the coefficients in the excitation model were deduced based on the direct inversion method and the inverse pseudo-excitation method, respectively. The coefficients in the excitation model were identified from the structural re-sponse. Finally, the annularly distributed random dynamic load was reconstructed based on the identified coefficients. Taking a satellite structural model subjected to annularly distributed random base excitation as a research object, the effectiveness of the proposed method was verified. The effects of the different identification methods, the level of measurement noise, the number of measuring points and the number of control points on the identification accuracy were also discussed. The results show that the error of the identified power spectral density and that of the spatial distribution are less than 2%, indicating that the method can provide a technical support for the prediction of load environment of aerospace crafts during service condition. [ABSTRACT FROM AUTHOR]

Background: Nonsyndromic cleft lip with or without cleft palate (NSCL/P) is one of the most common birth defects, and occurs in approximately 1/700 live births worldwide. The correlation between the ABCA4-ARHGAP29 region and NSCL/P was first identified by genome-wide association studies (GWAS), but few reports have examined NSCL/P caused by ARHGAP29 mutations in the Chinese population.Methods: We performed chromosome microarray analysis (CMA) for two consecutive abnormal fetuses and whole exome sequencing (WES) for the family, including 3 patients and 2 normal family members, Sanger sequencing and RT-PCR were used to confirm the mutation.Results: We identified a novel splice donor mutation (ARHGAP29 c.1920 + 1G > A) in two consecutive NSCL/P fetuses, and the variant was inherited from the mother and grandfather. The mutation caused abnormal skipping of exon 17, and the mRNA level of ARHGAP29 was significantly decreased compared to the wild type.Conclusions: In this study, we successfully diagnosed the genetic cause of NSCL/P in a family and first report that the c.1920 + 1G > A mutation in ARHGAP29 is associated with NSCL/P. Our study enriches the genetic landscape of NSCL/P, extends the mutation spectrum of ARHGAP29, and provides a new direction for the diagnosis of NSCL/P in patients and its prenatal diagnosis in fetuses. [ABSTRACT FROM AUTHOR]