Fabrication and Interface Structural Behavior of Mg/Al Thickness-Oriented Bonding Sheet via Direct Extrusion

Lei Gao,Feng Li,Ye Wang,Xing Mao Xiao,Peng Da Huo 대한금속·재료학회 2022 METALS AND MATERIALS International Vol.28 No.8

Solid-state bonding of heterogeneous materials is one of the effective ways to achieve light weight. An extrusion formingprocess for Mg/Al thickness-oriented bonding sheet was carried out. Due to triaxial compressive stress in the extrusion container,the AZ31 and AA6061 billets were deformed and the bonding and forming of Mg/Al thickness-oriented sheet can berealized by this method. The observation results of the bonding position by using XRD, SEM and EDS showed that: at theforming temperature with 360–420 °C, it had a good bonding interface, and the width of the transition layer increased withthe increase of the forming temperature. The presence of brittle intermetallic compounds in the transition layer indicated thatmetallurgical bonding had occurred at the interface. Considering all factors comprehensively, when the forming temperaturewas 390 °C, the bonding quality was appropriate. Its tensile-shear strength was 42 MPa, the width of the interface transitionlayer was about 10 μm, and the microhardness was about 164.3 HV. This method provided scientific guidance and technicalreserves for green forming of Mg/Al sheets.

Does Taekwondo Poomsae Training Impact on Body Composition, Physical Fitness, and Blood Composition in Children and Adolescents? A Systematic Review

Ye Lei,전형필 한국운동생리학회 2022 운동과학 Vol.31 No.1

PURPOSE: Numerous studies claim that Taekwondo can effectively help obese children improve their physical fitness. In addition, Taekwondo might help prevent lifestyle diseases and metabolic syndrome caused by obesity. However, studies and reviews on the effectiveness of Taekwondo Poomsae are very few compared to those on Taekwondo Kyorugi. Based on previous reviews, this study aims to clarify the effect of Taekwondo Poomsae training on improving body composition, physical fitness, and blood composition of children and adolescents of different groups. Furthermore, the applicability of Taekwondo Poomsae training is to be determined. METHODS: Two-hundred and two studies were searched via Korea electronic databases RISS, KISS, and DBPIA from March 1 to 3, 2021, and 22 of these were included in this review. RESULTS: Our review confirms that Taekwondo Poomsae is effective in improving the physical condition of developing children and adolescents. However, we cannot assert that this sport is also an effective exercise therapy for special youth groups, such as those who are overweight, obese, or have a metabolic growth or development syndrome. CONCLUSIONS: We suggest that sports implementers, Taekwando experts, coaches, and other sport professionals provide more Taekwondo Poomsae training programs suitable for physical and physiotherapeutic exercises for different ages and groups.

A Survey of Termitomyces (Lyophyllaceae, Agaricales), Including a New Species, from a Subtropical Forest in Xishuangbanna, China

( Lei Ye ),( Samantha C. Karunarathna ),( Huli Li ),( Jianchu Xu ),( Kevin D. Hyde ),( Peter E. Mortimer ) 한국균학회 2019 Mycobiology Vol.47 No.4

A survey of mushrooms was conducted in Xishuangbanna, Yunnan Province, China, in the rainy season (May to October) of 2012, 2013, and 2014, during which 16 specimens of Termitomyces were collected. Preliminary macro- and micro-characteristics, together with ITS sequence data, showed that four of the specimens belonged to a new species (Termitomyces fragilis), while the other 12 belonged to T. aurantiacus, T. eurrhizus, T. globules, T. microcarpus, and T. bulborhizus. In this paper, T. fragilis is introduced as a species new to science based on morphological characterization and phylogenetic analyses. Macro- and micro- morphological descriptions, color photographs and line drawings of the new species, and a phylogenetic tree to show the placement of the new species are provided. T. fragilis is then compared with other closely related taxa in the genus Termitomyces.

A Practical Seepage Model for Heat and Mass Transfer in Porous Media

Shu Ye Lei,Bu Xuan Wang 대한기계학회 1993 International Symposium on Transport Phenomena in Vol.1 No.1

Fabrication of self-reinforcement of porous mullite ceramic using NH4F as additive from kaolinite

Lei Yuan,Jingkun Yu,Rutao Ye,Shaowei Zhang 한양대학교 세라믹연구소 2013 Journal of Ceramic Processing Research Vol.14 No.4

Self-reinforcement of porous mullite ceramics containing needle-liked whiskers were fabricated from a powder mixture of kaolinite, Al(OH)3 and starch with NH4F as additive. The effects of the sintering temperature and the content of NH4F on porosity, phase composition, strength and microstructure of ceramics were investigated. The formation mechanism of needleliked mullite whiskers by in situ synthesis in ceramic body was discussed. The results indicated that lots of large aspect ratio needle-liked mullite whiskers, especially in the 15% NH4F additive sample, were observed. An interlocking structure was formed by needle-liked mullite whiskers to enhance the mechanical strength of porous mullite ceramic. And as the content of NH4F increasing, the bending strength increased. Comparing to the samples without NH4F additive, porous ceramic fabricated by adding NH4F showed a higher degree of mullitization. The formation mechanism of the needle-liked mullite in the ceramic was attributed to the reaction among NH4F and raw materials.

Garcinol, an Acetyltransferase Inhibitor, Suppresses Proliferation of Breast Cancer Cell Line MCF-7 Promoted by 17β-Estradiol

Ye, Xia,Yuan, Lei,Zhang, Li,Zhao, Jing,Zhang, Chun-Mei,Deng, Hua-Yu Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.12

The acetyltransferase inhibitor garcinol, a polyisoprenylated benzophenone, is extracted from the rind of the fruit of Garcinia indica, a plant found extensively in tropical regions. Anti-cancer activity has been suggested but there is no report on its action via inhibiting acetylation against cell proliferation, cell cycle progression, and apoptosis-inhibtion induced by estradiol ($E_2$) in human breast cancer MCF-7 cells. The main purposes of this study were to investigate the effects of the acetyltransferase inhibitor garcinol on cell proliferation, cell cycle progression and apoptosis inhibition in human breast cancer MCF-7 cells treated with estrogen, and to explore the significance of changes in acetylation levels in this process. We used a variety of techniques such as CCK-8 analysis of cell proliferation, FCM analysis of cell cycling and apoptosis, immunofluorescence analysis of NF-${\kappa}B$/p65 localization, and RT-PCR and Western blotting analysis of ac-H3, ac-H4, ac-p65, cyclin D1, Bcl-2 and Bcl-xl. We found that on treatment with garcinol in MCF-7 cells, $E_2$-induced proliferation was inhibited, cell cycle progression was arrested at G0/G1 phase, and the cell apoptosis rate was increased. Expression of ac-H3, ac-H4 and NF-${\kappa}B$/ac-p65 proteins in $E_2$-treated MCF-7 cells was increased, this being inhibited by garcinol but not ac-H4.The nuclear translocation of NF-${\kappa}B$/p65 in $E_2$-treated MCF-7 cells was also inhibited, along with cyclin D1, Bcl-2 and Bcl-xl in mRNA and protein expression levels. These results suggest that the effect of $E_2$ on promoting proliferation and inhibiting apoptosis is linked to hyperacetylation levels of histones and nonhistone NF-${\kappa}B$/p65 in MCF-7 cells. The acetyltransferase inhibitor garcinol plays an inhibitive role in MCF-7 cell proliferation promoted by $E_2$. Mechanisms are probably associated with decreasing ac-p65 protein expression level in the NF-${\kappa}B$ pathway, thus down-regulating the expression of cyclin D1, Bcl-2 and Bcl-xl.

OPNET을 이용한 OLSR과 AODV 라우팅 프로토콜 성능 비교

Ye Wang,Xiao-Lei Zhang,기장근,이규대 한국인터넷방송통신학회 2009 한국인터넷방송통신학회 논문지 Vol.9 No.3

Easy and Fast Synthesis of Pd-MWCNT/TiO₂ by the Sol-Gel Method and its Recyclic Photodegradation of Rhodamine B

Ye, Shu,Ullah, Kefayat,Zhu, Lei,Meng, Ze-Da,Sun, Qian,Oh, Won-Chun The Korean Ceramic Society 2013 한국세라믹학회지 Vol.50 No.4

Multiwalled carbon nanotubes (MWCNTs) modified with Pd and $TiO_2$ composite catalysts were synthesized by the sol-gel method followed by solvothermal treatment at low temperature. The chemical composition and surface structure were characterized by X-ray diffraction (XRD), energy-dispersive X-ray (EDX) spectroscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Photocatalytic recycle degradation experiments were carried out under both UV and visible light irradiation in the presence of MWCNT/$TiO_2$ and Pd-MWCNT/$TiO_2$ composites. As expected, the nanosized Pd-MWCNT/$TiO_2$ photocatalysts had enhanced activity over the non Pd treated MWCNT/$TiO_2$ material in the degradation of a rhodamine B (Rh.B) solution. An increase in photocatalytic activity was observed and attributed to an increase in the photo-absorption effect by MWCNTs and the cooperative effect of Pd and $TiO_2$ nanoparticles. According to the recycled results, the as-prepared Pd-MWCNT/$TiO_2$ sample had a good effect on it.

Novel Microwave Absorption Materials of Porous Flower-Like Nickel Oxide@Polyaniline in the X-Band

Ye Liu,Honglong Xing,Lei Wang,Zhenfeng Liu,Huan Wang,Hanxiao Jia 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.6

Porous flower nickel oxide@polyaniline (NiO@PANI) composites as excellent microwave absorption (MA) materials in the X-band were synthesized via a two-step strategy in this work. The porous NiO flower is uniformly dispersed and homogeneous in particle size after Ostwald ripening process. Coating conductive PANI on the surface of porous NiO microspheres could improve interfacial polarization and dielectric loss property that will lead to a great improvement of MA properties. Electromagnetic (EM) parameters of NiO@PANI composites with different NiO contents were investigated by a vector network analyzer and the reflection loss (RL) values with varied thickness were also calculated. The results showed that the effective absorption bandwidths (RL < -10 dB) of all NiO@PANI composites can cover the whole X-band. Especially, the NiO@PANI0.1 composite is able to attenuate microwave energy in the X-band with the thickness of 2.5mm. The NiO@PANI0.2 has a maximum RL of -32.8 dB at 10.1GHz and the effective absorption bandwidths cover 4.64GHz (11.12–15.76GHz) at 2.0mm. The excellent MA absorption performance may be ascribed to the polarization effect, dielectric loss and structure of porous flower-like NiO@PANI. Our work confirms that the synthesized NiO@PANI composite is an attractive candidate as a highly efficient MA material in the X-band.

Robust singular perturbation control for 3D path following of underactuated AUVs

Lei Ming,Li Ye,Pang Shuo 대한조선학회 2021 International Journal of Naval Architecture and Oc Vol.13 No.1

This paper presents a novel control scheme for the three-dimensional (3D) path following of underactuated Autonomous Underwater Vehicle (AUVs) subject to unknown internal and external disturbances, in term of the time scale decomposition method. As illustration, two-time scale motions are first artificially forced into the closed-loop control system, by appropriately selecting the control gain of the integrator. Using the singular perturbation theory, the integrator is considered as a fast dynamical control law that designed to shape the space configuration of fast variable. And then the stabilizing controller is designed in the reduced model independently, based on the time scale decomposition method, leading to a relatively simple control law. The stability of the resultant closed-loop system is demonstrated by constructing a composite Lyapunov function. Finally, simulation results are provided to prove the efficacy of the proposed controller for path following of underactuated AUVs under internal and external disturbances.