http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
- 中文 을 입력하시려면 zhongwen을 입력하시고 space를누르시면됩니다.
- 北京 을 입력하시려면 beijing을 입력하시고 space를 누르시면 됩니다.
RISS 인기검색어
- 검색키워드
- 저자 : Xueli Zhu (검색결과 6 건)
- 무료
- 기관 내 무료
- 유료
-
ENTROPY OF NONAUTONOMOUS DYNAMICAL SYSTEMS
Zhu, Yujun,Liu, Zhaofeng,Xu, Xueli,Zhang, Wenda Korean Mathematical Society 2012 대한수학회지 Vol.49 No.1
In this paper, the topological entropy and measure-theoretic entropy for nonautonomous dynamical systems are studied. Some properties of these entropies are given and the relation between them is discussed. Moreover, the bounds of them for several particular nonautonomous systems, such as affine transformations on metrizable groups (especially on the torus) and smooth maps on Riemannian manifolds, are obtained.
-
Entropy of nonautonomous dynamical systems
Yujun Zhu,Zhaofeng Liu,Xueli Xu,Wenda Zhang 대한수학회 2012 대한수학회지 Vol.49 No.1
In this paper, the topological entropy and measure-theoretic entropy for nonautonomous dynamical systems are studied. Some properties of these entropies are given and the relation between them is discussed. Moreover, the bounds of them for several particular nonautonomous systems, such as affine transformations on metrizable groups (especially on the torus) and smooth maps on Riemannian manifolds, are obtained.
-
Toughening of melamine–formaldehyde foams and advanced applications based on functional design
Bing Song,Xueli Zhu,Wei Wang,Liang Wang,Xiaoyuan Pei,Xiaoming Qian,Liangsen Liu,Zhiwei Xu 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.119 No.-
Owing to the intrinsic flame-retardancy, thermal stability, sound absorption, and easy processing, melamine–formaldehyde foams(MFs) have drawn substantial attention. Typically, the high-porosity and compressibilityof flexible MFs render them suitable for the construction of 3D templates and in thefabrication of porous N-doped carbon materials. But the widespread applications of MFs still suffer highbrittleness and low strength, calling for modifying and toughening MFs with more facile and economicalmethods, and much potential in advanced applications by functional design deserves further exploration. This review comprehensively summarized and evaluated the recent progress of the toughening methodsof MFs. We will also look into the applications of commercial MFs, carbonized MFs and foam-based compositesin flame retardancy and thermal management, oil/water separation, photothermal conversion,electrical energy storage, and other fields, aiming to give a guide for the preparation, modification, andexploitation of MFs both in traditional and emerging areas.
-
Investigation on characteristics of pressure fluctuation in a centrifugal pump with clearance flow
Lulu Zheng,Xiaoping Chen,Wei Zhang,Zu-chao Zhu,Jinglei Qu,Mengmeng Wang,Xiaojie Ma,Xueli Cheng 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.9
Clearance flow has great impact on pressure fluctuation of centrifugal pumps. Numerical calculations are performed to study the pressure fluctuation characteristics of centrifugal pump with wear ring clearance, especially in the regions of interaction between main flow and clearance flow (IMC) and clearance. The accuracy of numerical calculations is illustrated by comparing the experiments of performance and pressure fluctuation. Results show that, in clearance region the pressure fluctuation is still governed by blade passing frequency (f BPF ). Its amplitude of dominate frequency of pressure fluctuation becomes larger as the probe approaches the impeller exit. In IMC region, the pressure fluctuation at impeller outlet is dominated by f BPF . However, the dominate frequency at the entrance of impeller is less than f BPF . In addition, as the flow rate increased, the amplitude of dominate frequency of pressure fluctuation increases at impeller entrance, whereas an inverse trend is observed at wear ring clearance region.
-
Effects of clearance flow on the characteristics of centrifugal pump under low flow rate
Lulu Zheng,Xiaoping Chen,Hua-Shu Dou,Wei Zhang,ZuChao Zhu,Xueli Cheng 대한기계학회 2020 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.34 No.1
The Reynolds averaged Navier-Stokes equations and the shear stress transport k-ω turbulence model are employed to simulate the centrifugal pump with or without clearance flows. The simulation results have been compared with the experimental data and good agreement has been achieved. Results show that clearance flow causes a decrease in the characteristics of the centrifugal pump, particularly in pressure fluctuation. The largest deviation of the amplitude of pressure fluctuation between the centrifugal pump with and without clearance flow is 65.34 %. The numerical results also show that the clearance flow causes collision impact with the mainstream flow and forms a multiple vortex structure at the impeller entrance. Clearance flow greatly affects the pressure distribution in the impeller passage, which is opposite to the volute tongue, especially at the suction side of the blade surface. The wave distribution decreases along the direction of the hub to the shroud, which indicating that the influence of clearance flow weakens along this direction.
-
Yatian Chen,Bin He,Qiufei Chen,Hamza Malik,Hongqiang Zhu,Yuhang Wang,Jian He,Bomou Ma,Xueli Wang,Hui Zhang,Yong Liu 한국섬유공학회 2023 Fibers and polymers Vol.24 No.9
The effects of KBrO3 modification on polyacrylonitrile (PAN) precursor fibers at different modification temperatures were studied. The mechanical properties, chemical structure, aggregation structure, morphological structure, and thermal behavior of PAN precursor fibers were analyzed. The mechanical properties of PAN precursor fibers are essentially unaltered after KBrO3 modification, although oxygen-containing functional groups are introduced. KBrO3 can ionize bromate ion in aqueous solution, which has good nucleophilicity and can attack the positively charged carbon atom in C≡N, so that the cyclization proceeds according to the ionic mechanism, allowing the transformation of C≡N to C = N in the PAN precursor fibers generated a cyclic trapezoidal structure containing primary aromatic amine, which reduced the peak temperature of the cyclization reaction from 284.5 °C to 275.1 °C and decreased the heat release. The sp3-hybridized carbon structure changes into a sp2 hybridized C = C structure with increasing aromatization, according to XRD and Raman data, and the KBrO3 alteration accelerates the degradation of the original microcrystalline structure and transforms into a new polycyclic aromatic structure. The degree of conjugation and aromatization of the system rapidly increased with the rise in modification temperature. The stabilized fibers were discovered to have the lowest R-value, the highest aromatization, the smoothest surface, and the fewest flaws at impregnation temperature of 60 °C.
연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
