A modal approach for the efficient analysis of a bionic multi-layer sound absorption structure

Yonghua Wang,Chengyu Xu,Yanling Wan,Jing Li,Huadong Yu,Luquan Ren 국제구조공학회 2016 Steel and Composite Structures, An International J Vol.21 No.2

The interest of this article lies in the proposition of using bionic method to develop a new sound absorber and analyze the efficient of this absorber in a ski cabin. Inspired by the coupling absorption structure of the skin and feather of a typical silent flying bird — owl, a bionic coupling multi-layer structure model is developed, which is composed of a micro-silt plate, porous fibrous material and a flexible micro-perforated membrane backed with airspace. The finite element simulation method with ACTRAN is applied to calculate the acoustic performance of the multi-layer absorber, the vibration modal of the ski cabin and the sound pressure level (SPL) near the skier's ears before and after pasting the absorber at the flour carpet and seats in the cabin. As expected, the SPL near the ears was significantly reduced after adding sound-absorbing material. Among them, the model 2 and model 5 showed the best sound absorption efficiency and the SPL almost reduced 5 dB. Moreover, it was most effctive for the SPL reduction with full admittance configuration at both the carpet and the seats, and the carpet contribution seems to be predominant.

Application of the Multi-Source Data Fusion Algorithm in the Hail Identification

Yonghua Zhu,Yongqing Wang,Zhiqun Hu,Fansen Xu,Renqiang Liu 한국기상학회 2022 Asia-Pacific Journal of Atmospheric Sciences Vol.58 No.3

In this study, the canonical correlation analysis algorithm (CCA) is used to fuse the two-dimensional wind field retrieved from the single-Doppler weather radar, the three-dimensional wind field retrieved from the dual-Doppler weather radars, the observations from the ground automatic weather stations and the meteorological reanalysis data in three hail episodes (“0625” episode in Beijing, “0330” and “0801” episodes in Guangdong). During the hail episode in Beijing on June 25, 2020, an evident and long-lasting three-body scatter spike was observed, which played an important role in the hail identification and warning. In the three-dimensional wind field retrieved from the dual-Doppler weather radars, there is horizontal convergence of northeasterly and northwesterly winds and that of northwesterly and southeasterly winds in the low-level strong echo area, and there are obvious updrafts in the vertical wind field structure. Such a circulation configuration is favorable for the development and maintenance of hail storm. The multi-source data fusion of the wind fields can effectively improve the identification of the low-level convergence. The data fusion for the other two hail episodes (“0330” and “0801” episodes in Guangdong) yields the same conclusion. It is revealed that the dual-radar fusion performs better than the single-radar fusion in the identification of the meso-γ scale vortices. It can visually illustrate the characteristics of the cyclonic convergent flow fields which is more consistent with the near-surface observation. It can be concluded that the multi-source data fusion technique is practicable in the three severe convection processes.

Experimental and Numerical Study on the Stability Capacity of Q690 High-strength Circular Steel Tubes Under Axial Compression

Wang Hui,Guo Yonghua,Bai Yongtao,Zhang Bin,Sun Qing,Xue Jianyang 한국강구조학회 2017 International Journal of Steel Structures Vol.17 No.3

This paper presents experimental investigation on the local and overall buckling capacity of Q690 high-strength circular steel tubes under axial compression. Coupon tests are undertaken to obtain the Young’s modulus, Poisson’s ratio, tensile yield stress and ultimate tensile strength of Q690 steel material. Forty-two specimens under axial compression are tested to evaluate the buckling behavior and the failure mode. Test results indicate that most of the existing design standards are conservative for the design of Q690 steel tubes. The distribution model of residual stress is measured by cutting ring method. Then, a finite element model based on modified column deflection curve method (CDC) is built to assess the effects of initial imperfection and residual stress on the stability capacity of the steel tubes. Finally, design methods and recommendations are provided for estimating the stability capacity of high-strength circular steel tubes.

Risk Factors for Cognitive Impairment in High-Grade Glioma Patients Treated with Postoperative Radiochemotherapy

Qiang Wang,Fengxia Xiao,Fei Qi,Xiaopeng Song,Yonghua Yu 대한암학회 2020 Cancer Research and Treatment Vol.52 No.2

Purpose Fractionated radiotherapy as well as concomitant and adjuvant chemotherapy such as temozolomide for postoperative high-grade glioma (HGG) patients improves progressionfree survival and overall survival. Multiple factors such as chemotherapy, radiotherapy, tumor grade, residual tumor volume, and genetic modifications might play a role in the formation of cognitive impairment. The risk factors of cognitive impairment in postoperative patients with HGG receiving radiotherapy and chemotherapy remains a concern in this population. The purpose of this study was to identify risk factors for cognitive impairment in patients of postoperative HGG. Materials and Methods A total of 229 patients with HGG who underwent surgery were analyzed. Cognitive impairment was defined as a decrease of Cognitive Assessment Montreal (MoCA)’s score in at least two cognitive domains or any MoCA’s score of less than 26 points at the time of study compared with baseline level. Multiple potential risk factors including methylated status of the O6-methylguanine-DNA methyltransferase (MGMT) promoter, glioma World Health Organization (WHO) grade, residual tumor volume, education, and sex were analyzed. Cox univariate and multivariate regression analysis was used to detect the significant risk factors for cognitive impairment. Results At the end of follow-up among the 229 patients, 147 patients (67%) developed cognitive impairment. 82 patients (36%) remained in normal cognitive condition. In multivariate analysis, unmethylated MGMT promoter (hazard ratio [HR], 1.679; 95% confidence interval [CI], 1.212 to 2.326; p=0.002), glioblastoma (HR, 1.550; 95% CI, 1.117 to 2.149; p=0.009), and residual tumor volume > 5.58 cm3 (HR, 1.454; 95% CI, 1.047 to 2.020; p=0.026) were independent risk factors for cognitive impairment. Conclusion Methylated status of the MGMT promoter, glioma WHO grade, and residual tumor volume might be risk factors for the cognitive impairment in postoperative patients with HGG.

A Detection and Parameter Estimation Algorithm of Multicomponent Chirp Signals Based on Generalized S-Transform

Dianwei Wang,Jiulun Fan,Yonghua Li 보안공학연구지원센터(IJSIP) 2012 International Journal of Signal Processing, Image Vol.5 No.2

LES investigation into the generation of momentum deficits in the supersonic wake of a micro-ramp

Xiao Wang,Yonghua Yan,Zhengzhong Sun,Chaoqun Liu 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4

Implicitly implemented large eddy simulation (LES) with a fifth-order WENO scheme was conducted in this study. Based on Navier- Stokes equations, this LES was carried out to explore the origin of momentum deficit caused by a supersonic micro-ramp at flow conditions of Ma = 2.5 and Reθ = 5760. The numerical results were validated through qualitative and quantitative comparisons with existing experimental data. After describing the aerodynamic properties of the supersonic wake, such as the deficit and the streamwise vortices, the momentum deficit was later detected to originate from the lower portion of the upstream boundary layer, while the high momentum fluid originated from close to the wall at the upper portion. Position alternation trigged by the micro-ramp was finally proposed as a revised mechanism.

Amino acid, fatty acid, and carbohydrate metabolomic profiles with ginsenoside-induced insecticidal efficacy against Ostrinia furnacalis (Guenee)

Liu, Shuangli,Wang, Xiaohui,Zhang, Rui,Song, Mingjie,Zhang, Nanqi,Li, Wanying,Wang, Yingping,Xu, Yonghua,Zhang, Lianxue The Korean Society of Ginseng 2020 Journal of Ginseng Research Vol.44 No.4

Background: Previous studies have shown the insecticidal efficacy of ginsenosides. In the present study, we aimed to investigate the metabolic mechanism related to the inhibitory effect of panaxadiol saponins (PDSs) against the Asian corn borer Ostrinia furnacalis (Guenee). Methods: Third instar larvae of O. furnacalis were fed normal diets with different concentrations of PDSs for 4 days. The consumption index, relative growth rate, approximate digestibility, and conversion of ingested and digested food were recorded. A targeted gas chromatographye-mass spectrometry assay was performed to detect the profiles of amino acids, fatty acids, and carbohydrates in larvae of O. furnacalis. In addition, the activity of detoxification-related enzymes was determined. Results and Conclusions: PDSs decreased the consumption index, relative growth rate, approximate digestibility, and conversion of ingested and digested food in the 3rd instar larvae of O. furnacalis in a dose-dependent manner. PDSs decreased 15 free amino acids, 16 free fatty acids, and 5 carbohydrates and increased the levels of palmitoleic acid, palmitic acid, and 9-octadecenoic acid in the 3rd instar larvae. The activity of detoxification-related enzymes, such as acetylcholinesterase, glutathione S-transferase, cytochrome P450, carboxylesterase, trehalase, acid phosphatase, and alkaline phosphatase, was reduced in a dose-dependent manner in the 3rd instar larvae exposed to PDSs. These data confirmed the inhibitory effect of PDSs against growth, food utilization, and detoxification in the 3rd instar larvae of O. furnacalis and the potential for using PDSs as an efficient tool for insect pest management for O. furnacalis larvae.

Amino acid, fatty acid, and carbohydrate metabolomic profi les with ginsenoside-induced insecticidal effi cacy against Ostrinia furnacalis (Guenee)

Shuangli Liu,Xiaohui Wang,Rui Zhang,Mingjie Song,Nanqi Zhang,Wanying Li,Yingping Wang,Yonghua Xu,Lianxue Zhang 고려인삼학회 2020 Journal of Ginseng Research Vol.44 No.4

Background: Previous studies have shown the insecticidal efficacy of ginsenosides. In the present study,we aimed to investigate the metabolic mechanism related to the inhibitory effect of panaxadiol saponins(PDSs) against the Asian corn borer Ostrinia furnacalis (Guenee). Methods: Third instar larvae of O. furnacalis were fed normal diets with different concentrations of PDSsfor 4 days. The consumption index, relative growth rate, approximate digestibility, and conversion ofingested and digested food were recorded. A targeted gas chromatographyemass spectrometry assaywas performed to detect the profiles of amino acids, fatty acids, and carbohydrates in larvae ofO. furnacalis. In addition, the activity of detoxification-related enzymes was determined. Results and Conclusions: PDSs decreased the consumption index, relative growth rate, approximate digestibility,and conversion of ingested and digested food in the 3rd instar larvae of O. furnacalis in a dosedependentmanner. PDSs decreased 15 free amino acids, 16 free fatty acids, and 5 carbohydrates andincreased the levels of palmitoleic acid, palmitic acid, and 9-octadecenoic acid in the 3rd instar larvae. The activity of detoxification-related enzymes, such as acetylcholinesterase, glutathione S-transferase,cytochrome P450, carboxylesterase, trehalase, acid phosphatase, and alkaline phosphatase, was reducedin a dose-dependent manner in the 3rd instar larvae exposed to PDSs. These data confirmed theinhibitory effect of PDSs against growth, food utilization, and detoxification in the 3rd instar larvae ofO. furnacalis and the potential for using PDSs as an efficient tool for insect pest management forO. furnacalis larvae.

Review : The Role of Residues 103, 104, and 278 in the Activity of SMG1 Lipase from Malassezia globosa: A Site-Directed Mutagenesis Study

( Dongming Lan ),( Qian Wang ),( Grzegorz Maria Popowicz ),( Bo Yang ),( Qingyun Tang ),( Yonghua Wang ) 한국미생물 · 생명공학회 2015 Journal of microbiology and biotechnology Vol.25 No.11

The SMG1 lipase from Malassezia globosa is a newly found mono- and diacylglycerol (DAG) lipase that has a unique lid in the loop conformation that differs from the common alpha-helix lid. In the present study, we characterized the contribution of three residues, L103 and F104 in the lid and F278 in the rim of the binding site groove, on the function of SMG1 lipase. Sitedirected mutagenesis was conducted at these sites, and each of the mutants was expressed in the yeast Pichia pastoris, purified, and characterized for their activity toward DAG and pnitrophenol (pNP) ester. Compared with wild-type SMG1, F278A retained approximately 78% of its activity toward DAG, but only 11% activity toward pNP octanoate (pNP-C8). L103G increased its activity on pNP-C8 by approximately 2-fold, whereas F104G showed an approximate 40% decrease in pNP-C8 activity, and they both showed decreased activity on the DAG emulsion. The deletion of 103-104 retained approximately 30% of its activity toward the DAG emulsion, with an almost complete loss of pNP-C8 activity. The deletion of 103-104 showed a weaker penetration ability to a soybean phosphocholine monolayer than wild-type SMG1. Based on the modulation of the specificity and activity observed, a pNP-C8 binding model for the ester (pNP-C8, N102, and F278 form a flexible bridge) and a specific lipidanchoring mechanism for DAG (L103 and F104 serve as “anchors” to the lipid interface) were proposed.

Study on grinding mechanism and machining technology of Si3N4 ceramic spindle

Songhua Li,Chuang Li,Minghe Liu,Yonghua Wang,Chuang Zuo,Hao Zhang,Yifeng Gao 한양대학교 청정에너지연구소 2023 Journal of Ceramic Processing Research Vol.24 No.6

In order to improve the machining accuracy of the cylindrical surface of silicon nitride ceramic spindle, the machining technologyof the cylindrical surface of ceramic spindle was studied by high-speed universal cylindrical grinder in this experiment. Firstly, the primary and secondary order of the influence of various factors on the surface roughness of ceramic spindleis determined by orthogonal experiment, then the influence law of single grinding parameter on the surface roughness ofceramic spindle is explored by single factor experiment, and the prediction model of the grinding surface roughness value ofceramic spindle is calculated by numerical analysis software, and finally the optimal processing parameters of the cylindricalsurface of ceramic spindle are obtained. The experimental results show that the grinding surface roughness of silicon nitrideceramic spindle first decreases and then increases with the increase of grinding wheel linear speed and workpiece linearspeed, and then increases with the increase of transverse feed speed and axial feed speed. The relative error between the predictedvalue of the prediction model and the actual measured value is less than 5%, which shows that the prediction modelhas a good prediction effect and provides a theoretical basis for actual machining