Researching on X-Band Electromagnetic Interference Shielding Efficiency of MWCNTs Buckypapers Inserted with Mn Nanopowder

Shaowei Lu,Yaoyao Bai,Jijie Wang,Chenxu Zhao,Wei Li,Xiaoqiang Wang,Zhenwei Huang 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.6

Ultrathin multi-walled carbon nanotubes (MWCNTs) buckypapers inserted with Mn nanopowder were fabricated via vacuum filtration method, at a lower manufacturing cost and easier operation. The buckypapers were characterized structurally using scanning electron microscopy, energy-dispersive spectrometer and X-ray diffraction. Electromagnetic interference (EMI) shielding effectiveness (SE) of MWCNTs buckypapers inserted with Mn nanopowder (0–30 wt.%) were tested in X-band (8.2–12.4 GHz). When the blended Mn nanopowder content is 20 wt.%, the buckypaper exhibits much higher EMI SE of average value up to 42 dB with the thickness of only 0.11 mm. Further, this buckypaper is flexible and lightweight, and can be integrated with resin matrix composites. Thus, the results and techniques promise a simple and effective approach to achieve lightweight and ultrathin composite films for a wide application prospect in the field of EMI shielding and microwave absorption.

Genome-Wide Association Analysis to Search for New Loci Associated with Lifelong Premature Ejaculation Risk in Chinese Male Han Population

Wang Fei,Luo Defan,Chen Jianxiang,Pan Cuiqing,Wang Zhongyao,Fu Housheng,Xu Jianbing,Yang Meng,Mo Shaowei,Zhuang Liying,Ye Liefu,Wang Weifu 대한남성과학회 2022 The World Journal of Men's Health Vol.40 No.2

Purpose: Genetic factors play an indispensable role in the pathogenesis of lifelong premature ejaculation (LPE). The suscep-tibility genes/SNPs that have been discovered are very limited and can only explain part of the genetic effects of LPE. There-fore, discovering more genetic polymorphisms associated with the occurrence and development of LPE will help reveal the pathogenesis of LPE. Materials Materials and and Methods:Methods: We conducted a genome-wide association study of LPE in 486 Chinese male Han people (cases and controls). We used Gene Titan multi-channel instrument and Axiom Analysis Suite 6.0 software for genotyping. Imputation was performed by IMPUTE2 software and the 1000 Genomes Project (Phase3) was used as reference for haplotype. Finally, logistic regression analysis was performed on all loci that passed the quality control. The odds ratio and 95% confidence in-terval were calculated to determine the association between each SNPs and Chinese male Han population LPE risk. Results:Results: The results showed that a total of 33 genetic variants in 13 genes (LACTBL1 , SSBP3 , ACOT11 , LINC02486 , TMEM154, LINC01098, NONE, HCG27, HLA-C, TNFSF8, TNC, FAM53B, SULF2) have a suggestively significant genome-wide association with LPE risk (p<5×10-6). Conclusions:Conclusions: This study is the first to conduct a GWAS on LPE in Chinese male Han population 33 genetic polymorphisms have a suggestive genome-wide association with LPE risk. This study have provided data supplement for the genetic loci of LPE risk, and laid a scientific foundation for the pathogenesis and the targeted therapy of LPE.

Research on a New Hybrid Intelligent Fault Diagnosis Method and its Application

Zhenhua Wang,Zhentao Liu,Xueyan Lan,Jian Liu,Shaowei Wang,Yangming Wu,Yanbing Xue 보안공학연구지원센터 2016 International Journal of Smart Home Vol.10 No.7

In order to overcome the shortcomings of slow convergence speed and easy falling into the local minimum values of the BP neural network, an improved particle swarm optimization(PSO) algorithm is proposed to optimize the redial basic function (RBF) neural network, in order to propose a new hybrid intelligent fault diagnosis(IMPSO-RBFNN) method. In the IMPSO-RBFNN method, the adaptive dynamic adjusting strategy is used to control the inertia weight of the PSO algorithm in order to an improved particle swarm optimization(IMPSO) algorithm. Then the IMPSO algorithm is selected to optimize the parameters of RBF neural network by encoding the particle and continuous iteration of the IMPSO algorithm in order to obtain the optimal combination values of the parameters of RBF neural network. The optimal combination values are regarded as the values of these parameters of the RBFNN for constructing the final IMPSO-RBFNN method. In order to test the effectiveness of the proposed IMPSO-RBFNN method, the data from bearing data center of CWRU is selected in this paper. The experiment results show that the IMPSO algorithm can effectively optimize the weights of RBFNN, the IMPSO-RBFNN method can accurately realize high precision fault diagnosis of rolling bearing.

Flexible GnPs/EPDM with Excellent Thermal Conductivity and Electromagnetic Interference Shielding Properties

Shaowei Lu,Yaoyao Bai,Jijie Wang,Dandan Chen,Keming Ma,Qingshi Meng,Xinmin Liu 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2019 NANO Vol.14 No.6

As the portable device hardware has been increasing at a noticeable rate, ultrathin flexible materials with the combination of high thermal conductivity and excellent electromagnetic interference (EMI) shielding performance are urgently needed. Here, we fabricated ethylene propylene diene monomer rubber with different loading graphene nanoplatelets (GnPs/EPDM) by a cost-efficient approach, which combines mixing, ultrasonication and compression. Further investigation demonstrates that the 8 wt.% GnPs/EPDM with only 0.3 mm in thickness shows excellent electrical conductivity (28.3 S/m), thermal conductivity (0.79 W/mK) and good mechanical properties. Besides, the 8 wt.% GnPs/EPDM exhibits an EMI shielding effectiveness (SE) up to 33 dB in the X-band (8.2–12.4 GHz) and 35 dB in the Ku-band (12.4–18 GHz), superior to most of the reported rubber matrix. Additionally, the GnPs/EPDM shows excellent flexibility and stability with 95% and 94% retention of EMI SE even after repeated bending for 5000 times and corrosion (under 5% NaCl environment) for a week. Our flexible EMI shielding material will benefit the fast-growing next-generation commercial portable flexible electrons.

Research on experimental measurement of acoustic resistance and major accuracy influencing factors analysis

Wang Xiaoqing,Xiang Yang,Guo Zhiyong,Xia Xuebao,Shi Yuxiao,Xue Peng,Wu Shaowei 대한기계학회 2014 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.28 No.4

An experimental method of measuring acoustic surface radiation resistance is developed. The principle of the method is based on obtainingsource velocity and field pressure generated by the source. To measure surface radiation resistance, measuring probe was developedand measuring system was set up. Then, major factors that affect measurement accuracy is discussed and great improvements aregot. After that, experiments of measuring baffled circular piston were conducted to analyze its applicable frequency range. To verifyactual application effect, experiments of measuring the tube and cylinder heads of a diesel engine were performed. The results show thatthis measuring system can obtain resistance values in the frequency range from 460 to 1900 Hz with high precision. The measuring systemhas features of simple operation, convenient use, and high accuracy. Therefore, it can be used to determine surface resistance matrixof various structures.

A Note on the Fracture Behavior of Concrete Beams within Water Pressure under Different Loading Rates

Yang Wang,Shaowei Hu,Jun Lu,Yanmin Qiao 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.9

This study examined the experiment of the water fracture interactions in the concrete. In order to create water pressure in the crack, a sealing device consisting of a mechanical clamp device and a waterproof membrane was proposed. Firstly, eighteen three-point bending tests were carried out to verify the proposed sealing device under three different loading rates. Subsequently, twelve hydraulic tests were performed under different loading rates. The results showed that the sealing device had minimal influence on the fracture behavior of concrete. Besides, with the increase of internal water pressure, the carrying capacity, fracture parameters and crack opening rate of concrete beam were evidently decreased. Meanwhile, the decrease of the carrying capacity, fracture parameters, and crack opening rate induced by internal water pressure decreased with the increase of loading rate. In addition, a significant hydraulic fracturing behavior caused by water pressure was observed in the quasi-static state.

Mapping the Mangrove Forest Restoration Potential and Conservation Gaps in China Based on Random Forest Model

Zhonghua Yu,Wei Li,Shaowei Zhang,Buqing Zhong,Jun Wang,이시영,최재혁,Shulin Deng 인간식물환경학회 2022 인간식물환경학회지 Vol.25 No.4

Background and objective: The area of mangroves is gradually decreasing globally, and mangroves are already one of the most threatened ecosystems. Despite net growth in the mangrove areas in China, the restoration potential of mangroves is still insufficient. This study proposed the Random forest model as an excellent data mining method to map the restoration potential based on the predicted probability of mangrove habitat suitability. Methods: We demonstrated the vital environmental variables influencing habitat suitability. The de-cisive advantages of RFM were parsimonious (variables selection), cost-effective (us-ing existing open-source data), accurate (training AUC was 0.89, testing AUC was 0.91), highly efficient (fast-training speed); and its results had high explanatory power. Here, we first mapped the conservation gaps using the RFM. Results: The results showed that temperature was the most important environmental factor influencing the habitat suit-ability of mangroves. The northern limit of suitable areas was around 24°44' N. The theoretical suitable habitat area for mangrove was 196,566.6 ha (the highly suitable area was 32,551.4 ha, the medium suitable area was 164,015.2 ha). The potential area for mangrove restoration was 176,264 ha (Guangdong with 104215.4 ha, Guangxi with 65957.5 ha). Conclusion: We proposed 24 sites with conservation gaps for mangrove forests restoration and nine potential sites as examples for the further restoration plan. We took one example site with high restoration potential for further explanation: how the key environmental factors influence the habitat suitability and how to use the infor-mation to guide the restoration strategies. RFM can be used as a data mining algo-rithm for the utmost use of the presence-only ecological data, objectively evaluating the suitability of species distribution, and providing scientifically technical data for species restoration planning.

Effect of solution properties on the interaction of 90Sr(II) with GMZ bentonite

Xin Chen,Jin Wang,Shaowei Wang,Fengliang Ma,Xiaopeng Chen,Jiaxing Li 한국화학공학회 2015 Korean Journal of Chemical Engineering Vol.32 No.11

The bentonite from gaomiaozi county (Inner Mongolia, China) (GMZ bentonite) has been selected as the candidate of backfill material in China for nuclear waste repository. Herein, the sorption of 90Sr(II) on GMZ bentonite was investigated as a function of contact time, solid content, pH, ionic strength, foreign ions, humic acid (HA) and temperature. The results indicated that the sorption of 90Sr(II) was mainly dominated by ion exchange or outer-sphere surface complexation at low pH, whereas inner-sphere surface complexation was the main sorption mechanism at high pH values. The thermodynamic parameters (ΔH0, ΔS0 and ΔG0) calculated from the temperature-dependent sorption isotherms indicated that the sorption of 90Sr(II) on GMZ bentonite was an endothermic and spontaneous process. The results provided important information for the interaction mechanism of 90Sr(II) with GMZ bentonite, and is crucial for the evaluation of GMZ bentonite as backfill material.

FRP Flexural Strengthened Concrete Member Design Method of Based on Early-Warning Fuses

Rong Guo,Shuo Ning,Shaowei Zhao,Minghao Wang 대한토목학회 2020 KSCE JOURNAL OF CIVIL ENGINEERING Vol.24 No.11

The bearing capacity of members strengthened with prestressed carbon fiber reinforced plastic is improved significantly, however, the ductility of the members strengthened are reduced obviously. Moreover, no sign are observed before the failure and the failure process rapidly. The current study proposed a reinforcement method based on early-warning fuses theory to address this issue and took carbon fiber reinforced plastic as an example. First, it's necessary to determine the area of carbon fiber board and the application of prestressed in each part of the member (early-warning fuses part and load-bearing part). This needs to be determined by the basic safety reserve and the additional safety reserve of the carrying capacity, then the calculation formula are derived; second, designing six simulation beams and four test beams. Based on the comparison of the computation of the derived formula with the simulation and test results, the calculated values of the early-warning load agree well with the simulated and experimental values, and the calculated values of the ultimate load are less than the simulated and experimental values. This showed that the theoretical calculation method has high accuracy. In addition, various evaluation index prove that the members strengthened have sufficient reserves.

Effects of subsequent curing on chloride resistance and microstructure of steam-cured mortar

Hu, Yuquan,Hu, Shaowei,Yang, Bokai,Wang, Siyao Techno-Press 2020 Advances in concrete construction Vol.9 No.5

The influence of subsequent curing on the performance of fly ash contained mortar under steam curing was studied. Mortar samples incorporated with different content (0%, 20%, 50% and 70%) of Class F fly ash under five typical subsequent curing conditions, including standard curing (ZS), water curing(ZW) under 25℃, oven-dry curing (ZD) under 60℃, frozen curing (ZF) under -10℃, and nature curing (ZN) exposed to outdoor environment were implemented. The unsteady chloride diffusion coefficient was measured by rapid chloride migration test (RCM) to analyze the influence of subsequent curing condition on the resistance to chloride penetration of fly ash contained mortar under steam curing. The compressive strength was measured to analyze the mechanical properties. Furthermore, the open porosity, mercury intrusion porosimetry (MIP), x-ray diffraction (XRD) and thermogravimetric analysis (TGA) were examined to investigate the pore characteristics and phase composition of mortar. The results indicate that the resistance to chloride ingress and compressive strength of steam-cured mortar decline with the increase of fly ash incorporated, regardless of the subsequent curing condition. Compared to ZS, ZD and ZF lead to poor resistance to chloride penetration, while ZW and ZN show better performance. Interestingly, under different fly ash contents, the declining order of compressive strength remains ZS>ZW>ZN>ZD>ZF. When the fly ash content is blow 50%, the open porosity grows with increase of fly ash, regardless of the curing conditions are diverse. However, if the replacement amount of fly ash exceeds a certain high proportion (70%), the value of open porosity tends to decrease. Moreover, the main phase composition of the mortar hydration products is similar under different curing conditions, but the declining order of the C-S-H gels and ettringite content is ZS>ZD>ZF. The addition of fly ash could increase the amount of harmless pores at early age.