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 : Siwei Zhang (검색결과 5 건)
- 무료
- 기관 내 무료
- 유료
-
Duan Chunzheng,Zhang Fangyuan,Qin Siwei,Sun Wei,Wang Minjie 대한기계학회 2018 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.32 No.9
White layer formed in hard cutting process has great influence on surface quality of the workpiece, simulation of the white layer has great significance. Dynamic recrystallization critical temperature model is derived to calculate the critical temperature of the dynamic recrystallization in the white layer. A finite element model was developed to simulate the hard cutting process based on the JohnsonCook constitutive equation. The dynamic recrystallization critical temperature was derived based on the true stress-strain curves obtained by the split Hopkinson pressure bar experiments. The cellular automaton model which aims to simulate the white layer grains formed by the dynamic recrystallization process in hard cutting is established. The temperature and strain data extracted from the finite element model are used in the cellular automaton model. The contrast between the simulation and experimental results demonstrates that the cellular automaton model can simulate the dynamic recrystallization process in the white layer accurately. The dynamic recrystallization processes in the white layer under different cutting speed and flank wear are simulated based on the finite element - cellular automaton model. The results show that the dynamic recrystallization grain size of the white layer decreases with the increase in cutting speed and tool wear.
-
Synthesis of CdxZn1-xS@MIL-101(Cr) Composite Catalysts for the Photodegradation of Methylene Blue
Shipeng Yang,Siwei Peng,Chunhui Zhang,Xuwen He,Yaqi Cai 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2018 NANO Vol.13 No.10
Nanoparticles of the semiconductor catalyst CdxZn1-xS were embedded into the metal organic framework MIL-101(Cr) to obtain CdxZn1-xS@MIL-101(Cr) nanocomposites. These materials not only possess high surface areas and mesopores but also show good utilization of light energy. The ultraviolet-visible diffuse reflectance patterns of CdxZn1-xS@MIL-101(Cr) nanocomposites showed that Cd0.8Zn0.2S@MIL-101(Cr) possessed good visible light response ability among the synthesized nanocomposites. The photocatalytic performance of the CdxZn1-xS@MIL-101(Cr) nanocomposites were tested via degradation and mineralization of methylene blue in neutral water solution under light irradiation using a 300W xenon lamp. As a result, using Cd0.8Zn0.2S@MIL-101(Cr) as a catalyst, 99.2% of methylene blue was mineralized within 30 min. Due to the synergistic effect of adsorption by the MIL-101(Cr) component and photocatalytic degradation provided by the Cd0.8Zn0.2S component, the Cd0.8Zn0.2S@MIL-101(Cr) catalyst displayed superior photocatalytic performance relative to Cd0.8Zn0.2S and MIL-101(Cr). Furthermore, Cd0.8Zn0.2S@MIL-101(Cr) possessed excellent stability during photo-degradation and exhibited good reusability. The remarkable photocatalytic performance of Cd0.8Zn0.2S@MIL-101(Cr) is likely due to the effective transfer of electrons and holes at the heterojunction interfaces.
-
Jianping Shen,Siwei Zhang,Wei Wang,Shuguang Li,Song Zhang,Yujun Wang 한국광학회 2021 Current Optics and Photonics Vol.5 No.3
A tapered As 2 S 3 photonic crystal fiber (PCF) with four layers of air holes in a hexagonal array around the core is designed in this paper. Numerical simulation shows that the dispersion D decreases and the nonlinearity coefficient γ increases from the thick to the thin end along the tapered PCF. We simulate the midinfrared pulse compression in the tapered As 2 S 3 PCF using the adaptive split-step Fourier method. Initial Gaussian pulses of 4.4 ps and a central wavelength of 2.5 μm propagating in the tapered PCF arelocated in the anomalous dispersion region. With an average power of assumed input pulses at 3 mW and a repetition frequency of 81.0 MHz, we theoretically obtain a pulse duration of 56 fs and a compression factor of 78 when the pulse propagates from the thick end to the thin end of the tapered PCF. When confinement loss in the tapered PCF is included in the simulation, the minimum pulse duration reaches 72 fs; correspondingly, the maximum compression factor reaches 61. The results show that in the anomalous-dispersion region, midinfrared pulses can be efficiently compressed in a dispersion-decreasing and nonlinearity-increasing tapered As 2 S 3 PCF. Due to confinement loss in the tapered fiber, the efficiency of pulse compression is suppressed.
-
Chen Xu,Boyu Zhang,Siwei Liu,Qingtian Su 국제구조공학회 2020 Steel and Composite Structures, An International J Vol.35 No.3
The steel-concrete double composite girder in the negative flexural region combines an additional concrete slab to the steel bottom flange to prevent the local steel buckling, however, the additional concrete slab may lower down the neutral axis of the composite section, which is a sensitive factor to the tensile stress restraint on the concrete deck. This is actually of great importance to the structural rationality and durability, but has not been investigated in detail yet. In this case, a series of 5.5 m-long composite girder specimens were tested by negative bending, among which the bottom slab configuration and the longitudinal reinforcement ratio in the concrete deck were the parameters. Furthermore, an analytical study concerning about the influence of bottom concrete slab thickness on the cracking and sectional bending-carrying capacity were carried out. The test results showed that the additional concrete at the bottom improved the composite sectional bending stiffness and bending-carrying capacity, whereas its effect on the concrete crack distribution was not obvious. According to the analytical study, the additional concrete slab at the bottom with an equivalent thickness to the concrete deck slab may provide the best contributions to the improvements of crack initiation bending moment and the sectional bending-carrying capacity. This can be applied for the design practice.
-
Peng Jiang,Xiujuan Fu,Hong Niu,Siwei Chen,Feifei Liu,Yu Luo,Dan Zhang,Hui Lei 대한약학회 2023 Archives of Pharmacal Research Vol.46 No.6
Strains of the fungal genus Pestalotiopsis are reported as large promising sources of structurally varied biologically active metabolites. Many bioactive secondary metabolites with diverse structural features have been derived from Pestalotiopsis. Moreover, some of these compounds can potentially be developed into lead compounds. Herein, we have systematically reviewed the chemical constituents and bioactivities of the fungal genus Pestalotiopsis, covering a period ranging from January 2016 to December 2022. As many as 307 compounds, including terpenoids, coumarins, lactones, polyketides, and alkaloids, were isolated during this period. Furthermore, for the benefit of readers, the biosynthesis and potential medicinal value of these new compounds are also discussed in this review. Finally, the perspectives and directions for future research and the potential applications of the new compounds are summarized in various tables.
DBpia
ScienceON연관 검색어 추천
이 검색어로 많이 본 자료
활용도 높은 자료
