Bonding Strength of Conductive Inner-Electrode Layers in Piezoelectric Multilayer Ceramics

Wang, Yiping,Yang, Ying,Zheng, Bingjin,Chen, Jing,Yao, Jinyi,Sheng, Yun The Korean Institute of Electrical and Electronic 2017 Transactions on Electrical and Electronic Material Vol.18 No.4

Multilayer ceramics in which piezoelectric layers of $0.90Pb(Zr_{0.48}Ti_{0.52})O_3-0.05Pb(Mn_{1/3}Sb_{2/3})O_3-0.05Pb(Zn_{1/3}Nb_{2/3})O_3$ (0.90PZT-0.05PMS-0.05PZN) stack alternately with silver electrode layers were prepared by an advanced low-temperature co-fired ceramic (LTCC) method. The electrical properties and bonding strength of the multilayers were associated with the interface morphologies between the piezoelectric and silver-electrode layers. Usually, the inner silver electrodes are fabricated by sintering silver paste in multi-layer stacks. To improve the interface bonding strength, piezoelectric powders of 0.90PZT-0.05PMS-0.05PZN with an average particle size of $23{\mu}m$ were added to silver paste to form a gradient interface. SEM observation indicated clear interfaces in multilayer ceramics without powder addition. With the increase of piezoelectric powder addition in the silver paste, gradient interfaces were successfully obtained. The multilayer ceramics with gradient interfaces present greater bonding strength as well as excellent piezoelectric properties for 30~40 wt% of added powder. On the other hand, over addition greatly increased the resistance of the inner silver electrodes, leading to a piezoelectric behavior like that of bulk ceramics in multilayers.

Numerical Simulation of a Torrential Rain Event in the Northeast of Huaihe Basin. Part II: Instability Conditions and the Mechanism of Intensification and Maintenance

Yiping Wang,Yinong Pan,Yuan Wang 한국기상학회 2011 Asia-Pacific Journal of Atmospheric Sciences Vol.47 No.1

Based on the simulation displayed in Part I of this study,the intensification and maintenance, the relationship between deep moist mesoscale convective system (DMMCS) and instability, convective vorticity vector (CVV) are analyzed in the present paper. Results show that: (1) middle-low level convective instability is the precondition of the occurrence of DMMCS. The convergence and merger enhancement of convection cells, as well as the convective instability energy transporting from the left-front of typhoon play an essential role in the re-establishment and enhancement of convective instability. (2) Baroclinic instability and conditional symmetric instability appear not only in the middle-low level, but also are distinct in the middleupper level of DMMCS. (3) In DMMCS, there is an alternative distribution of inertial instability column and inertial stability column. In the west and south, there are negative CVV columns, which is favorable for the burst of deep moist convection. (4) The strong slantwise convection induced by inertial instability, baroclinic instability,and conditional symmetric instability enhance the upper-level southerly component. Due to the appearance of the compensated downdraft at the low level of south side of DMMCS, the low level southerly intensified, and the enhancement of upper- and low-level cores is in favor of the development of DMMCS, which will be beneficial to the reinforcement and maintenance of inertial instability,baroclinic instability, and conditional symmetric instability. It is a positive feedback process. (5) There is a downshear circulation to the east of rainfall cell. Shallow convections near this cell absorb the vapor and instability energy coming from the south. In the meanwhile, the mesoscale convergence line and meso-β-scale vortex organize and intensify convective cells. In DMMCS, there is an alternative distribution of convergence and divergence columns, and the couple between strong divergence and vorticity columns. They are both conducive to the development of DMMCS, and the instability will be intensified and maintained for its development in depth.

Bonding Strength of Conductive Inner-Electrode Layers in Piezoelectric Multilayer Ceramics

Yiping Wang,Ying Yang,Bingjin Zheng,Jing Chen,Jinyi Yao,Yun Sheng 한국전기전자재료학회 2017 Transactions on Electrical and Electronic Material Vol.18 No.4

Multilayer ceramics in which piezoelectric layers of 0.90 Pb(Zr0.48Ti0.52)O3 -0.05 Pb(Mn1/3Sb2/3)O3 -0.05 Pb(Zn1/3Nb2/3)O3(0.90PZT-0.05PMS-0.05PZN) stack alternately with silver electrode layers were prepared by an advanced low-temperatureco-fired ceramic (LTCC) method. The electrical properties and bonding strength of the multilayers were associated with theinterface morphologies between the piezoelectric and silver-electrode layers. Usually, the inner silver electrodes are fabricatedby sintering silver paste in multi-layer stacks. To improve the interface bonding strength, piezoelectric powders of0.90PZT-0.05PMS-0.05PZN with an average particle size of 23 μm were added to silver paste to form a gradient interface. SEMobservation indicated clear interfaces in multilayer ceramics without powder addition. With the increase of piezoelectricpowder addition in the silver paste, gradient interfaces were successfully obtained. The multilayer ceramics with gradientinterfaces present greater bonding strength as well as excellent piezoelectric properties for 30~40 wt% of added powder. Onthe other hand, over addition greatly increased the resistance of the inner silver electrodes, leading to a piezoelectric behaviorlike that of bulk ceramics in multilayers.

A Energy-aware Clustering Algorithm via Game Theory for Wireless Sensor Networks

Yiping Yang,Chuan Lai,Lin Wang,Xiaofan Wang 제어로봇시스템학회 2012 제어로봇시스템학회 국제학술대회 논문집 Vol.2012 No.10

Multihop communication mechanism has been widely employed in wireless sensor networks (WSNs) for its practicability and high energy efficiency. However, hot spots emerge as locations, in which nodes die quickly because of heavy relay load, leading to disruption in network service. Balancing energy consumption of nodes so as to mitigate the hot spot issue in the network is very important for prolonging network lifetime. In this paper, we propose a distributed clustering algorithm, namely Game Theoretic Clustering(GTC), which can approach to the equilibrium of the energy consumption for the wireless network. Especially, the cluster size is determined adaptively based on the game theory and the cooperation between cluster heads. Simulation results show that GTC can balance the energy consumption levels and consequently extend the network lifetime.

Effect of Leukocyte-Platelet Rich Fibrin (L-PRF) on Tissue Regeneration and Proliferation of Human Gingival Fibroblast Cells Cultured Using a Modified Method

Mudalal Mahmoud,Wang Zhanqi,Mustafa Shockry,Liu Yiping,Wang Yao,Yu Jize,Wang Shengnan,Sun Xiaolin,Zhou Yanmin 한국조직공학과 재생의학회 2021 조직공학과 재생의학 Vol.18 No.5

Background: An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology. Methods: Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit—8 assay. Results: A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration. Conclusion: The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields. Background: An in vitro study on rapid culturing method of human gingival fibroblast cells (HGFCs) was established to investigate the potential use of the leukocyte-platelet rich fibrin (L-PRF) in tissue engineering technology, different medical fields, including periodontology and implantology. Methods: Eight biopsies were obtained from eight different donors and a modified culturing technique was developed to obtain HGFCs. The modified 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide MTT assay was used to compare the cell viability when the modified culturing method was used in comparison to the standard method. Blood samples were collected from the same patients and L-PRF was isolated using a standard protocol. The releases of platelet-derived growth factor-AA and transforming growth factor-beta1 at various time intervals were observed using enzyme-linked immunosorbent assay (ELISA) kit. The proliferative effect of L-PRF on HGFCs was assessed by the cell counting kit—8 assay. Results: A simple and rapid modified method for in vitro HGFC culture yielded a cellular monolayer within three to nine days after cell culture. L-PRF with three-dimensional polymer fibers released growth factors that peaked during the first three hours and continued to produce up to 10 days. The L-PRF presented a dose-dependent effect on HGFCs proliferation where HGFCs proliferation increased with an increase in L-PRF concentration. Conclusion: The modified technique for the culture of HGFCs might be useful for the development of future experimental and clinical studies, besides L-PRF has great therapeutic potential in oral surgery fields.

A review of the species in the genus Synergus Hartig (Hymenoptera: Cynipidae: Synergini) from mainland China, with an updated key to the Eastern Palaearctic and Oriental species

Lobato-Vila Irene,Wang Yiping,Melika George,Guo Rui,Ju Xiaoxue,Pujade-Villar Juli 한국응용곤충학회 2021 Journal of Asia-Pacific Entomology Vol.24 No.1

The Eastern Palaearctic and Oriental fauna of gall wasp inquilines (Hymenoptera: Cynipidae) has been histori cally understudied. Previously, ten species of Synergus Hartig (Hymenoptera: Cynipidae: Synergini), the most speciose genus of inquilines associated with Fagaceae galls worldwide, were known to occur in mainland China despite this region harbors a great number of potential fagaceous tree hosts. After the examination of all the Synergus specimens deposited at the Parasitic Hymenoptera Collection of the Agriculture and Forestry University of Zhejiang (ZAFU, China), we provide a revision of this genus in mainland China. Three new species (S. drouarti Pujade-Villar, sp. nov., S. ponsatiae Lobato-Vila & Pujade-Villar, sp. nov. and S. rovirae Lobato-Vila & PujadeVillar, sp. nov.) are described and illustrated. Four species (S. areolatus (Weld, 1926) comb. nov.; S. formosanus Schwéger & Melika, 2015, S. gifuensis Ashmead, 1904 and S. ishikarii Melika & Schwéger, 2015) are new records for this area. Saphonecrus reticulatus Pujade-Villar, Wang & Guo, 2014 is proposed as syn. nov. of Synergus castaneus Pujade-Villar, Bernardo & Viggiani, 2013, and Synergus changtitangi Melika & Schwéger, 2015 as syn. nov. of S. deqingensis Pujade-Villar, Wang & Chen, 2015. We provide new biological and distributional data for all the species as well as redescriptions, pictures and other corrections for those which were originally poorly characterized. Lastly, we provide an updated key to the Eastern Palaearctic and Oriental Synergus species, with a table summarizing all of them.

Low Power and High Speed Network on Chip Architecture for BP Neural Network

Yiping Dong,Yinghe Li,Yang Wang,Takahiro Watanabe 대한전자공학회 2009 ITC-CSCC :International Technical Conference on Ci Vol.2009 No.7

Back Propagation Artificial Neural Network (BP-ANN), one of widely used neural networks, has been used in a lot of areas. Hardware architecture of BP-ANN was proposed by using an NoC (Network on Chip) and implemented on FPGA. In this paper, new NoC architecture which has a torus topology and IXY (Intelligent XY) routing algorithm is developed for BP-ANN to make it low power and high performance. This system is implemented by FPGA to estimate system performance and power consumption. NIRGAM NoC simulator is also used to evaluate latency and throughput of this system. Experimental results show that our proposed architecture can increase Connection Per Second (CPS) about 2 times than existing digital hardware ANN; it can reduce communication load which total packet size can reduce about 3.2 times compared with traditional packet transmit method of BP-ANN. It can reduce latency by 23.7% and dynamic power consumption by 7.2% compare with the former NoC architecture BP-ANN. It is reconfigurable and expandable to meet various ANN applications. Furthermore other type ANNs can also be implemented in the system by adjusting a routing algorithm of NoCs.

A Coupled Recursive Total Least Squares-Based Online Parameter Estimation for PMSM

Wang, Yangding,Xu, Shen,Huang, Hai,Guo, Yiping,Jin, Hai The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.6

A coupled recursive total least squares (CRTLS) algorithm is proposed for parameter estimation of permanent magnet synchronous machines (PMSMs). TLS considers the errors of both input variables and output ones, and thus achieves more accurate estimates than standard least squares method does. The proposed algorithm consists of two recursive total least squares (RTLS) algorithms for the d-axis subsystem and q-axis subsystem respectively. The incremental singular value decomposition (SVD) for the RTLS obtained by an approximate calculation with less computation. The performance of the CRTLS is demonstrated by simulation and experimental results.

Fabrication, Densification and Thermionic Emission Property of Lanthanum Hexaboride

Yiping Yu,Song Wang,Wei Li,Hongmei Chen,Zhaohui Chen 대한금속·재료학회 2018 ELECTRONIC MATERIALS LETTERS Vol.14 No.5

An effective way to improve sintering densification of LaB6was proposed and confirmed experimentally. Firstly, LaB6nanopowders with a cube-like shape of ~ 94.7 nm were fabricated by molten salt synthesis route at 800 °C for 1 h. Then,LaB6bulk material of 98% density was prepared by hot pressing sintering of as-synthesized LaB6nanopowders under1800 °C/50 MPa/30 min. The acquired LaB6bulk material had a work function of 2.87 eV and exhibited an excellentthermionic emission property. The saturation emission current density at 1500 and 1600 °C reached 37.4 and 44.3 A/cm2,respectively.

Research on Temperature Field of a New Type of Magnetorheological Fluid Dynamometer with Cooling System

Lei Wang,YiPing Luo,Hui Ying Liang,Meng Ji 한국자기학회 2019 Journal of Magnetics Vol.24 No.4

In order to study the temperature characteristics of magnetorheological fluid dynamometer, the torque model and working principle of magnetorheological fluid dynamometer were analyzed, the temperature experiment of magnetorheological fluid dynamometer was conducted, and the experimental data were analyzed and processed in this paper. The fitting curves between the speed of magnetorheological fluid dynamometer and the experimental temperature, the speed and the torque, the current and the torque as well as the current and the temperature were obtained. Then, the temperature field of magnetorheological fluid was simulated by FLUENT based on the experimental data. The temperature field nephograms and temperature values of test points under different working conditions were obtained. Comparing the experimental values with the simulation values, the relative error was less than 7.8 %, which was within a reasonable range. Finally, from the aspect of temperature reduction, the simulation model was optimized. Based on the principle of heat convection, the simulation model was reconstructed. The maximum temperature drop was 10℃.