Core–Shell Chain-Like Cu@Ni Composite with Dual Absorption Peaks to Improve Microwave Absorption Properties

Yuanyuan Zhou,Jianying Deng,Shimei Li,Zefeng Li 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.5

Core–shell Cu@Ni chains were successfully synthesized through a mild hydrothermal reaction. The morphology, structure and microwave electromagnetic properties of the composite were then characterized by X-ray diffraction, energy-dispersive spectroscopy, scanning electron microscopy and vector network analysis. The formation mechanisms of the core–shell structure and one-dimensional chains were ascribed to the varying redox potentials of Cu and Ni ions and the magnetic dipole–dipole attraction. Furthermore, a minimal reflection loss (RL) of -20.7 dB was observed at 9.6 GHz with a thickness of 2.0mm and the effective absorption ( ≤10 dB, 90% microwave attenuation) bandwidth can be adjusted between 5.2 GHz and 16.6 GHz for the thin absorber thickness of 2.0–4.0 mm. The novel core–shell chain-like Cu@Ni alloy can be used as a promising absorbing material because it shows numerous features such as thin thickness, strong absorption, low cost and lightweight.

Experimental Analysis of Vertical Deformation and Bearing Characteristics of Bridge Piles in High and Steep Slopes

Yuanyuan Wang,Ronggui Deng,Tao Guo,Yi Sun,Bo Huang,Qinke Wang 대한토목학회 2023 KSCE Journal of Civil Engineering Vol.27 No.3

More and more rigid frame bridges with high piers and large spans are built in the high and steep slope areas of deep valleys in southwest China. The slow deformation of the slope in the geological sense often causes the problems of piles, which in turn causes damage of the upper bridges. The vertical bearing characteristics of bridge piles in slope still need to be conducted because of the peculiarity of slope topography. The vertical deformation and bearing characteristics of piles in the slope area were experimentally studied by considering different influencing factors and the fitting formula for the ultimate bearing capacity of the piles under vertical load is obtained. The results show that the vertical deformation and ultimate bearing capacity (defined by vertical limit settlement deformation of 0.013 times the pile diameter) of the pile are closely related to its position in the slope. The pile in the middle of the slope has the lowest vertical ultimate bearing capacity. Moreover, the side frictional resistance transfer depth of the pile in continuous slope is greater than that of the pile in unilateral slope. Additionally, the slope angle has a significant influence on the vertical bearing performance of piles. The delayed settlement of the pile top decreases approximately 40% at most and the vertical ultimate bearing capacity of the pile increases 48.6% at most as the slope angle decreases by 15°. Meanwhile, the side friction resistance of the pile increases with the decrease of slope angle. The bending moment applied to the pile top reduces the vertical ultimate bearing capacity of the pile and increases the axial force of the pile body. The results can provide data support for pile design and instability judgment with similar geological conditions.

Carbon Paper-Supported NiCo/C–N Catalysts Synthesized by Directly Pyrolyzing NiCo-Doped Polyaniline for Oxygen Reduction Reaction

Zhongliang Deng,Qingfeng Yi,Yuanyuan Zhang,Huidong Nie,Guang Li,Liang Yu,Xiulin Zhou 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.1

In this study, we report the findings that the C–N composites containing Ni and Co (Ni1Co1/C–N, Ni3Co1/C–N, Ni6Co1/C–N, Ni9Co1/C–N, Ni10Co0/C–N and Ni0Co10/C–N) can be produced by direct pyrolysis of the NiCo-doped polyaniline (PANI) precursors in N2 atmosphere at 800 ℃ and show efficient electroactivity for oxygen reduction reaction (ORR) in alkaline media. Distribution and compositions of the catalysts were characterized by SEM, TEM, EDS and XRD techniques. The catalysts were loaded on carbon paper to prepare gas diffusion electrodes, in which electrocatalytic activity for ORR in alkaline media was investigated by voltammetric techniques. The ORR current density on these carbon paper-supported NiCo/C–N catalysts exhibits a linear increase with the negative shift of ORR potential. The ORR onset potential is around 0.2 V (versus Ag/AgCl) in alkaline media. Among the prepared catalysts, the catalyst Ni6Co1/C–N presents the largest ORR current density, which is 68.5 mA cm -2@-0.8 V (versus Ag/AgCl) in alkaline media. Moreover, Ni6Co1/C–N catalyst also presents good electrocatalytic activity stability for ORR.

Thrust distribution characteristics of thrust systems of shield machines based on spatial force ellipse model in mixed ground

Kongshu Deng,Yuanyuan Li,Zhurong Yin 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.1

The objective of this research is to investigate force distribution characteristics for propelling system of tunneling machines in mixedground. First, a mechanical model for pushing system in composite strata is constructed. Then, eccentricity trunk is determined usingspatial force ellipse eccentricity to measure the degree of uniformity of forces applied on rear segments in a thrust system. Finally, theeccentricity trunk is used to the thrust system of a tunneling machine applied in engineering. Force distribution performance of variousarrangements with equal quantities of jacks is discussed in detail. Results from virtual prototype simulation prove the numerical analyticalresults. A theoretical foundation and support is provided for the design of non-equidistant pushing system of tunneling machines undercomposite stratum.

중국 지역 간의 정보격차와 G2C전자정부서비스의 이용의도에 관한 연구

YU DENG SHENG,ZHANG YUANYUAN,Gyoo Gun Lim 한국IT서비스학회 2020 한국IT서비스학회 학술대회 논문집 Vol.2020 No.1

2000년대부터 중국 경제성장을 주도하는 정보통신산업에 대해 집중적으로 육성함으로써 정보통신기술이 급속한 속도로 발전하여 확산되었다. 그러나 지역 간의 경제성장이 빠른 지역과 그렇지 못한지역 간의 정보통신기술의 확산 속도 및 스마트 기기 보급의 격차는 여전히 심한 것으로 나타났다.인터넷 및 정보통신기술을 기반으로 전자정부서비스를 이용자 수가 지속적으로 증가하고 있지만 지역경제가 높은 도시와 낮은 도시 간에 전자정부서비스의 활용지수의 격차가 여전히 큰 것으로 현성 되어 있다. 본 연구는 정보격차의 변수인 접근성, 역량성, 활용성 및 역기능가 G2 C전자정부서비스의 이용의도에 어떠한 영향을 미치는 지에 파악하여 밝히고자 한다. 또한 인구사 회학적 특성 및 지역특성측면에 지각된 정보격차의 차이가 존재하는 지에 검토하여 확인하고자 한다. 본 연구의 결과를통해 지능정보사회에 더욱 편리하고 스마트할 수 있는 전자정부서비스를 구축 시에 기본 자료가될 수 있도록 기대된다. 또한 향후 중국 지역 간의 정보격차를 해소할 수 있는 방안을 모색함으로써 전자정부서비스 시민활용성 및 활성화에 기여할 수 있는 것으로 기대된다.

지능정보사회에서의 중국지역간 정보격차와 지각된 학업성과에 관한 연구

YU DENG SHENG,ZHANG YUANYUAN,SONG ZHANMEI,임규건(Gyoo Gun Lim) 한국IT서비스학회 2019 한국IT서비스학회 학술대회 논문집 Vol.2019 No.2

2000년대부터 중국 경제성장을 주도하는 핵심적 산업인 정보통신산업에 대해 집중적으로 육성 및 지원함으로써 정보통신기술의 사회적 확산도 매우 빠른 속도로 진전되었다. 그러나 정보통신 기술산업의 생산품과 개인 소득의 측면에서 지역 간의 경제성장이 빠른 지역과 그렇지 못한 지역간의 정보통신기술의 확산 속도 및 보급의 격차는 여전히 심한 것으로 나타났다. 또한 중국인터넷발전상황통계보고에 따르면 도시와 농촌의 인터넷 보급률을 살펴보면 보급률은 모두 증가세를 보이지만 격차는 여전히 큰 것으로 확인할 수 있다. 본 연구는 정보격차가 지각된 학업성과에 어떠한 영향을 미치는 지에 파악하고자 한다. 또한지역 간의 정보격차에 따른 지각된 학업성과의 차이가 존재하는 지에 확인하고자 한다. 향후 중국 지역 간의 정보격차를 해소할 수 있는 방안을 모색함으로써 교육성과를 제고하고 교육역량 활성화에 기여할 수 있는 것으로 기대된다.

Modification of Wool via Grafting β-cyclodextrin Oxidized by Sodium Periodate

Chaoqian Lou,Yuanyuan Yin,Xiuzhi Tian,Haibo Deng,Yingxia Wang,Xue Jiang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.8

The modification of wool fabrics is significant in preparation of functional textiles. Sodium periodate oxidized β-cyclodextrin was grafted onto wool fabric through Schiff base reaction to obtain fabric with controlled release property. β-cyclodextrin was oxidized to aldehyde-β-cyclodextrin, and the results show that the inclusion constant and aldehyde contentof aldehyde-β-cyclodextrin are varied with the reaction parameters such as molar ratio of reaction agents and the reactiontemperature. The degree of oxidation was confirmed by ion chromatography. The drug loading test shows that the oxidizedcyclodextrin still had inclusion ability towards phenolphthalein, while the inclusion constant was only 50 % of the original β-CD. The ATR-FTIR spectra proved the occurrence of grafting reaction between the aldehyde groups of aldehyde-β-cyclodextrin and the amino groups on wool fiber. The aldehyde-β-cyclodextrin grafted wool fabric show great washingdurability even after 5 washing cycles. Compared with the aldehyde-β-cyclodextrin power, the inclusion ability of aldehyde-β-cyclodextrin fixed on the wool fiber decreased by 60 %.

Hydrophilic Finishing of PET Fabrics by Applying Chitosan and the Periodate Oxidized β-cyclodextrin for Wash Resistance Improvement

Chaoqian Lou,Yuanyuan Yin,Xiuzhi Tian,Haibo Deng,Yingxia Wang,Xue Jiang 한국섬유공학회 2020 Fibers and polymers Vol.21 No.1

β-cyclodextrin (β-CD) was oxidized by sodium periodate to yield a mixture of dialdehyde oligosaccharides. Theperiodate-oxidized β-CD (O-β-CD) together with chitosan (CTS) was firstly used to finish poly(ethylene terephthalate)(PET) fabrics by immersion-padding method, in which O-β-CD acted as a hydrophilic finishing agent plus a cross-linker. Theprocesses including the periodate oxidization of β-CD and the CTS/O-β-CD hydrophilic finishing of PET fabrics were ecofriendly. The results from the hydroxylamine hydrochloride titration showed that the aldehyde content in O-β-CD was3.0 mmol/g. With increasing the CTS/O-β-CD mass ratio, the finished fabric had better hydrophilic properties. When theCTS/O-β-CD mass ratio was 1:1, the moisture regain and water drops wetting time of the finished fabric reached 1.85 % and5.06 s, respectively. They became 1.50 % and 5.70 s, respectively after 25 times of laundering cycle. The occurrence of crosslinkingbetween O-β-CD and CTS was confirmed by the gel test and FT-IR characterization. The cross-linking networkdeposited on the fiber surface brought on excellent wash resistance of the CTS/O-β-CD finished PET fabrics.

Early IL-17A Prevention Rather Than Late IL-17A Neutralization Attenuates Toluene Diisocyanate-Induced Mixed Granulocytic Asthma

Chen Shuyu,Yu Li,Deng Yao,Liu Yuanyuan,Wang Lingwei,Li Difei,Yang Kai,Liu Shengming,Tao Ailin,Chen Rongchang 대한천식알레르기학회 2022 Allergy, Asthma & Immunology Research Vol.14 No.5

Purpose: Interleukin (IL)-17A plays a critical role in the pathogenesis of allergic airway inflammation. Yet, the exact roles of IL-17A in asthma are still controversial. Thus, the aim of this study was to dissect the roles of IL-17A in toluene diisocyanate (TDI)-induced mixed granulocytic asthma and to assess the effects of neutralizing antibody in different effector phases on TDI-induced asthma. Methods: IL-17A functions in allergic airway inflammation were evaluated using mice deficient in IL-17A (Il17a−/−) or IL-17A monoclonal antibody (IL-17A mab, intraperitoneally, 50 μg per mouse, 100 μg per mouse). Moreover, the effects of exogenous recombinant IL (rIL)-17A in vivo (murine rIL-17A, intranasally, 1 μg per mouse) and in vitro (human rIL-17A, 100 ng/mL) were investigated. Results: TDI-induced mixed granulocytic airway inflammation was IL-17A-dependent because airway hyperreactivity, neutrophil and eosinophil infiltration, airway smooth muscle thickness, epithelium injury, dysfunctional T helper (Th) 2 and Th17 responses, granulocytic chemokine production and mucus overproduction were more markedly reduced in the Il17a−/− mice or by IL-17A neutralization during the sensitization phase of wild-type (WT) mice. By contrast, IL-17A neutralization during the antigen-challenge phase aggravated TDI-induced eosinophils recruitment, with markedly elevated Th2 response. In line with this, instillation of rIL-17 during antigen sensitization exacerbated airway inflammation by promoting neutrophils aggregation, while rIL-17A during the antigen-challenge phase protected the mice from TDI-induced airway eosinophilia. Moreover, rIL-17A exerted distinct effects on eosinophil- or neutrophil-related signatures in vitro. Conclusions: Our data demonstrated that IL-17A was required for the initiation of TDI-induced asthma, but functioned as a negative regulator of established allergic inflammation, suggesting that early abrogation of IL-17A signaling, but not late IL-17A neutralization, may prevent the progression of TDI-induced asthma and could be used as a therapeutic strategy for severe asthmatics in clinical settings.

Raman scattering investigations on Co-doped ZnO epitaxial films: Local vibration modes and defect associated ferromagnetism

Qiang Cao,Shumin He,Yuanyuan Deng,Dapeng Zhu,Xiaodong Cui,Guolei Liu,Huai-Jin Zhang,Shishen Yan,Yanxue Chen,Liangmo Mei 한국물리학회 2014 Current Applied Physics Vol.14 No.5

Raman scattering spectroscopy has been performed on high quality Co-doped ZnO epitaxial films, which were grown on Al2O3 (0001) by oxygen-plasma assisted molecular beam epitaxy. Raman measurements revealed two local vibration modes (LVMs) at 723 and 699 cm1 due to the substitution of Co2þ in wurtzite ZnO lattice. The LVM at 723 cm1 is found to be an elemental sensitive vibration mode for Co substitution. The LVM at 699 cm1 can be attributed to enrichment of Co2þ bound with oxygen vacancy, the cobalteoxygen vacancyecobalt complexes, in Zn1xCoxO films associated with ferromagnetism. The intensity of LVM at 699 cm1, as well as saturated magnetization, enhanced after the vacuum annealing and depressed after oxygen annealing.