Site effects by generalized inversion technique using strong motion recordings of the 2008 Wenchuan earthquake

The generalized inversion of S-wave amplitude spectra from the free-field strong motion recordings of the China National Strong Motion Observation Network System （NSMONS） are used to evaluate the site effects in the Wenchuan area. In this regard, a total of 602 recordings from 96 aftershocks of the Wenchuan earthquake with magnitudes of M3.7-M6.5 were selected as a dataset. These recordings were obtained from 28 stations at a hypocenter distance ranging from 30 km to 150 km. The inversion results have been verified as reliable by comparing the site response at station 62WUD using the Generalized Inversion Technique （GIT） and the Standard Spectral Ratio method （SSR）. For all 28 stations, the site predominant frequency F and the average site amplification in different frequency bands of 1.0-5.0 Hz, 5.0-10.0 Hz and 1.0-10.0 Hz have been calculated based on the inversion results. Compared with the results from the horizontal-to-vertical spectral ratio （HVSR） method, it shows that the HVSR method can reasonably estimate the site predominant frequency but underestimates the site amplification. The linear fitting between the average site amplification for each frequency band and the V20 （the average uppermost-20 m shear wave velocity） shows good correlation. A distance measurement called the asperity distance DAspt is proposed to reasonably characterize the source-to-site distance for large earthquakes. Finally, the inversed site response is used to identify the soil nonlinearity in the main shock and aftershocks of Wenchuan earthquake. In ten of the 28 stations analyzed in the main shock, the soil behaved nonlinearly, where the ground motion level is apparently beyond a threshold ofPGA 〉 300 cm/s^2 or PGV 〉 20 cm/s, and only one station coded 51SFB has evidence of soil nonlinear behavior in the aftershocks.

PREPARATION OF WATERBORNE ULTRAFINE PARTICLES OF EPOXY RESIN BY PHASE INVERSION TECHNIQUE

Waterborne ultrafine particles of epoxy resin were prepared by phase inversion technique. The results of SEM revealed that the particles diameter was in the range of 50 to 100 nm and the effects on amount of water required at phase inversion point were also discussed.

Modified hepatic left lateral lobe inversion in laparoscopic proximal gastrectomy: An analysis of 13 cases

BACKGROUND In laparoscopic proximal gastrectomy(LPG),the prolapse of the hepatic left lateral lobe near the lesser curvature and esophageal hiatus can obstruct the field of vision and operation.Therefore,it is necessary to retract or obstruct the hepatic left lateral lobe to ensure a clear field of vision.AIM To investigate the safety and clinical efficacy of the modified hepatic left lateral lobe inversion technique for LPG.METHODS A retrospective analysis was conducted on the clinical data of 13 consecutive patients with early-stage upper gastric adenocarcinoma or adenocarcinoma of the esophagogastric junction treated with LPG from January to December 2023 at the Department of Gastrointestinal Surgery,Second Affiliated Hospital of Fujian Medical University.The modified hepatic left lateral lobe inversion technique was used to expose the surgical field in all patients,and short-term outcomes were observed.RESULTS In all 13 patients,the modified hepatic left lateral lobe inversion technique was successful during surgery without the need for re-retraction or alteration of the liver traction method.There were no instances of esophageal hiatus occlusion,eliminating the need for forceps to assist in exposure.There was no occurrence of intraoperative hepatic hemorrhage,hepatic vein injury,or hepatic congestion.No postoperative digestive complications of Clavien-Dindo grade≥II occurred wi-thin 30 days after surgery,except for a single case of pulmonary infection.Some patients experienced increases in alanine aminotransferase and aspartate aminotransferase levels on the first day after surgery,which significantly decreased by the third day and returned to normal by the seventh day after surgery.CONCLUSION The modified hepatic left lateral lobe inversion technique has demonstrated satisfactory results,offering ad-vantages in terms of facilitating surgical procedures,reducing surgical trauma,and protecting the liver.

Study on T700/Cyanate/PS/Epoxy Composites with ex-situ Toughening Technique

Composites were prepared with polysulfone through ex-situ toughening technique. The dynamic parameters of cyanate/epoxy resin were studied by differential scanning calorimetric（DSC） analysis and dynamic mechanical analysis（DMA）. Microstructual toughening mechanism was studied through scanning electron microscopy（SEM）. The particle microstructure in interlaminar region of composites toughened through ex-situ toughening technique revealed that a reaction induced phase decomposition and phase inversion happened in the interlaminar region. The thermosetting particles were surrounded by the PS phase, which could signifi cantly improve the delamination resistance of composites. The compression after impact（CAI） can be signifi cantly improved from 180 MPa to 260 MPa by using ex-situ toughening while the mechanical properties are not affected.

Crustal attenuation characteristics of S-waves beneath the Eastern Tohoku region,Japan

An inversion method was applied to crustal earthquakes dataset to find S-wave attenuation characteristics beneath the Eastern Tohoku region of Japan. Accelerograms from 85 shallow crustal earthquakes up to 25 km depth and magnitude range between 3.5 and 5.5 were analyzed to estimate the seismic quality factor Qs. A homogeneous attenuation model Qs for the wave propagation path was evaluated from spectral amplitudes, at 24 different frequencies between 0.5 and 20 Hz by using generalized inversion technique. To do this, non-parametric attenuation functions were calculated to observe spectral amplitude decay with hypocentral distance. Then, these functions were parameterized to estimate Qs. It was found that in Eastern Tohoku region, the Qs frequency dependence can be approximated with the function 33 f 1.22 within a frequency range between 0.5 and 20 Hz. However, the frequency dependence of Qs in the frequency range between 0.5 and 6 Hz is best approximated by Qs （f） = 36 f 0.94 showing relatively weaker frequency dependence as compared to the relation Qs （f） = 6 f^ 2.09 for the frequency range between 6 and 15 Hz. These results could be used to estimate source and site parameters for seismic hazard assessment in the region.

An Alternating Direction Method of Multipliers for Inverse Lithography Problem

We propose an alternating direction method of multipliers(ADMM)to solve an optimization problem stemming from inverse lithography.The objective functional of the optimization problem includes three terms:the misfit between the imaging on wafer and the target pattern,the penalty term which ensures the mask is binary and the total variation regularization term.By variable splitting,we introduce an augmented Lagrangian for the original objective functional.In the framework of ADMM method,the optimization problem is divided into several subproblems.Each of the subproblems can be solved efficiently.We give the convergence analysis of the proposed method.Specially,instead of solving the subproblem concerning sigmoid,we solve directly the threshold truncation imaging function which can be solved analytically.We also provide many numerical examples to illustrate the effectiveness of the method.

ILT Approach for Compensating 3-D Mask Effects

As mask features scale to smaller dimensions, the so-called ＂3-D mask effects＂ which have mostly been neglected before, become important. This paper properly models the 3-D thick mask effects, and then analyses the object-based inverse lithography technique using a simulated annealing algorithm to determine the mask shapes that produce the desired on-wafer results. Evaluations against rigorous simulations show that the synthesized masks provide good image fidelity up to 0.94, and this approach gives improved accuracy and faster results than existing methods.