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Low-temperature activation of methane over rare earth metals promoted Zn/HZSM-5 zeolite catalysts in the presence of ethylene

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Journal of Natural Gas Chemistry 2011年第3期20卷 243-248页

作者： hengqiang Zhang Aiguo Kong Yongjie Ding chengyong Dai Yongkui Shan Department of Chemistry East China Normal University Shanghai 200062 China

At low temperature of 723 K, methane can be easily activated in the presence of ethylene in the feed, and converted to higher hydrocarbons （C2-C4） and aromatics （C6-C10）, through its reaction over rare metals modified Zn/HZSM-5 zeolite catalysts without undesirable carbon oxides formation. Methane can get 37.3% conversion over the above catalysts under low temperature, and the catalysts show a longer lifetime than usual metal supported HZSM-5 zeolite catalysts without adding any rare earth metals. The effects of methane activation over various rare earth metal promoted Zn/HZSM-5 catalysts on the products and influences of several reaction conditions such as temperature, catalyst lifetime and molar ratio of CH4/C2H4 have been discussed.

关键词： methane conversion HZSM-5 catalyst rare earth promoted

Predication of topological states in the allotropes of group-Ⅳ elements

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Frontiers of Physics 2021年第6期16卷 120-127页

作者： chengyong Zhong National Laboratory of Solid State Microstructures and Department of Physics Nanjing University Collaborative Innovation Center of Advanced Microstructures Nanjing University Institute for Advanced Study Chengdu University

Three-dimensional(3 D) topological insulators(TIs) have been studied for approximately fifteen years,but those made from group-IV elements, especially Ge and Sn, seem particularly attractive owing to their nontoxicity, sizable intrinsic spin–orbit coupling(SOC) strength and natural compatibility with the current semiconductor industry. However, group-IV elemental TIs have rarely been reported,except for the low temperature phase of α-Sn under strain. here, based on first-principles calculations,we propose new allotropes of Ge and Sn, named T5-Ge/Sn, as desirable TIs. These new allotropes are also highly anisotropic Dirac semimetals if the SOC is turned off. To the best of our knowledge,T5-Ge/Sn are the first 3 D allotropes of Ge/Sn that possess topological states in their equilibrium states at room temperature. Additionally, their isostructures of C and Si are metastable indirect and direct semiconductors. Our work not only reveals two promising TIs, but more profoundly, we justify the advantages of group-IV elements as topological quantum materials(TQMs) for fundamental research and potential practical applications, and thus reveal a new direction in the search for desirable TQMs.

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Application of rare-earth and nano elements on diamond cup wheels

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金刚石与磨料磨具工程 2007年第5期27卷 5-9页

作者： Cheng Yunping Wang chengyong Hu Yingning Wu Wenge School of Mechanical Engineering and Automation North University of China Taiyuan 030051 China） Guangdong University of Technology Guangzhou 510090 China） Department of Mechanical Engineering Guangxi University Nanning 530004 China）

Diamond cup wheel is used widely as an important tool for machining ceramic *** this paper,nano rare-earth oxide and nano carbide were added in the segments of seven kinds of diamond cup *** performance of diamond cup wheels were tested on a special designed test machine by grinding two kinds of ceramic *** surface morphology of the segments was examined by Scanning Election Microscopy(SEM) and the micro-hardness of segments was *** results showed that nano rare-earth oxide and nano carbide can fine segment micro structure,make grain boundary clear and increase grasping of diamond *** can increase also the wear resistance of diamond cup wheels as well as the grinding ratio.

关键词：金刚石杯状轮瓷砖纳米稀土氧化物碳纳米管

Engagement Angle Modeling for Multiple-circle Continuous Machining and Its Application in the Pocket Machining

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Chinese Journal of Mechanical Engineering 2017年第2期30卷 256-271页

作者： Shixiong WU Wei MA Haiping BAI chengyong WANG Yuexian SONG Mechanical and Electrical Engineering Institute GuangdongUniversity of TechnologyGuangzhou 510006China

The progressive cutting based on auxiliary paths is an effective machining method for the material accumulating region inside the mould pocket. But the method is commonly based on the radial depth of cut as the control parameter, further more there is no more appropriate adjustment and control approach. The end-users often fall to set the parameter correctly, which leads to excessive tool load in the process of actual machining. In order to make more reasonable control of the machining load and toolpath, an engagement angle modeling method for multiplecircle continuous machining is presented. The distribution mode of multiple circles, dynamic changing process of engagement angle, extreme and average value of engage- ment angle are carefully considered. Based on the engagement angle model, numerous application techniques for mould pocket machining are presented, involving the calculation of the milling force in multiple-circle continuous machining, and rough and finish machining path planning and load control for the material accumulating region inside the pocket, and other aspects. Simulation and actual machining experiments show that the engagement angle modeling method for multiple-circle continuous machining is correct and reliable, and the related numerous application techniques for pocket machining are feasible and effective. The proposed research contributes to the analysis and control tool load effectively and tool-path planning reasonably for the material accumulating region inside the mould pocket.

关键词： Pocket · Engagement angle · Milling force Circle · High·speed machining

A novel tunnel waterproof-drainage system based on double-bonded waterproofing materials and its seepage characteristics

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Frontiers of Structural and Civil Engineering 2024年第9期18卷 1321-1336页

作者： Xiaohe SUN Chenghua SHI Guoqing XIAO Yangyang GE chengyong CAO School of Civil Engineering Central South UniversityChangsha 410075China PowerChina ZhongNan Engineering Corporation Limited Changsha 410014China State Key Laboratory of Special Functional Waterproof Materials Beijing Oriental Yuhong Waterproof Technology Co.Ltd.Beijing 101111China College of Civil and Transportation Engineering Shenzhen UniversityShenzhen 518060China

Double-bonded spray membrane waterproofing materials have excellent waterproofing performance and can improve the load-bearing capacity of tunnel linings,leading to an increasing global ***,due to the double-bonded capability of spray membrane materials,traditional interlayer drainage methods cannot be *** limitation makes it difficult to use them in drainage-type tunnels,significantly restricting their range of *** this regard,a novel tunnel waterproof-drainage system based on double-bonded spray membrane materials was proposed in this *** proposed drainage system primarily comprises upper drainage sheets and bottom drainage blind pipes,both located in the tunnel circumferential direction,as well as longitudinal drainage pipes within the ***,numerical calculation methods are employed to analyze the seepage characteristics of this system,revealing the water pressure distribution around the *** results indicate that in the novel waterproof-drainage system,the water pressure in the secondary lining exhibits a“mushroom-shaped”distribution in the circumferential direction,while the water pressure in the longitudinal direction exhibits a“wave-like”***,comparative results with other waterproof-drainage systems indicate that under typical working conditions with a water head of 160 m and a rock permeability coefficient of 10^(−6)m/s,the maximum water pressure in the secondary lining of the novel waterproof-drainage system is 0.6 *** represents a significant reduction compared to fully encapsulated waterproofing and traditional drainage systems,which respectively reduce the water pressure by 65%and 30%.The applicability analysis of the double-bonded waterproofing and drainage system reveals that it can reduce at least 40%of the static water pressure in any groundwater *** novel drainage system provides a valuable reference for the application of double-bonded spray membr

关键词： tunnel drainage spray-applied waterproofing membrane numerical simulation water pressure

Structural transformations of carboxyl acids networks induced by concentration and oriented external electric field

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Chinese Chemical Letters 2021年第1期32卷 480-484页

作者： Wei Li Shilin Xu Xiaoling Chen chengyong Xu School of Science Nanchang Institute of TechnologyNanchang 330099China

The effects of concentration and an oriented external electric field on the transformations of hydrogenbonded structures of trimesic acid(TMA) and terephthalic acid(TPA) have been investigated at a liquidsolid interface by scanning tunneling microscopy(STM).The triangular periodic TMA framework can be transformed into a flower-like structure by changing the STM sample bias sign in *** of TMA and TPA are porous at a negative substrate bias,but typically change to relatively compact forms when the polarity of the applied bias is *** change is reversible if the applied bias is *** effects have potentials to locally control the capture and release of analytes in host-guest systems and the 2D morphology in multicomponent layers.

关键词： Concentration Electric field Structural transformation Scanning tunneling microscopy

Dynamics and Small Signal Stability Analysis of PMSG-based Wind Farm with an MMC-HVDC System

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CSEE Journal of Power and Energy Systems 2020年第1期6卷 226-235页

作者： Yifan Wang chengyong Zhao Chunyi Guo Atiq Ur Rehman The State Key Laboratory of Alternate Electrical Power System with Renewable Energy Sources North China Electric Power UniversityBeijing 102206China

The permanent magnet synchronous generator (PMSG)-based wind farm with a modular multilevel converter (MMC) based HVDC system exhibits various oscillations and can experience dynamic instability due to the interactions between different controllers of the wind farm and MMC stations, which have not been properly examined in the existing literatures. This paper presents a dynamic modeling approach for small signal stability analysis of PMSG-based wind farms with a MMC- HVDC system. The small signal model of the study system is validated by the comprehensive electromagnetic transient (EMT) simulations in PSCAD/EMTDC. Then the eigenvalue approach and participation factors analysis are utilized to comprehensively evaluate the impact of different controllers, system’s parameters and the circulating current suppressing controller (CCSC) on the small signal stability of the entire system. From eigenvalue analysis, it is revealed that as the output active power of the wind farm increases within the rated range, the overall system will exhibit a sub-synchronous oscillation (SSO) instability mode, an extremely weak damping mode, and a low frequency oscillation instability mode. From participation factors analysis, it is observed that the SSO mode and weak damping mode are primarily related to the internal dynamics of the MMC, which can be suppressed or improved by CCSC. It is determined that the low frequency oscillation mode is primarily caused by the interactions between the phase locked loop (PLL) control of the wind farm and the voltage and frequency (V-F) control of the MMC station. The analysis also depicts that the larger proportional gain value of the V-F control of the MMC station and smaller PLL bandwidth of the wind farm can enhance the small signal stability of the entire system.

关键词： HVDC modular multilevel converter(MMC) permanent magnet synchronous generator(PMSG) small signal stability sub-synchronous oscillation(SSO) wind farm

Catalytic oxidation effect of MnSO_(4) on As(Ⅲ) by air in alkaline solution

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Journal of Environmental Sciences 2023年第4期126卷 644-655页

作者： Yuhu Li Yudong Yang Ruixiang Wang Zhifeng Xu Guizhong Jin chengyong Jin Faculty of materials Metallurgy and Chemistry Jiangxi University of Science and TechnologyGanzhou 341000China Hsikwang Shan Twinkling Star Co.Ltd. Lengshui Jiang 417500China

The catalytic oxidation effect of MnSO_(4)on As(Ⅲ) by air in an alkaline solution was *** to the X-ray diffraction (XRD),scanning electron microscope-energy dispersive spectrometer (SEM-EDS) and X-ray photoelectron spectroscopy (XPS) analysis results of the product,it was shown that the introduction of MnSO_(4)in the form of solution would generate Na_(0.55)Mn_(2)O_(4)·1.5H_(2)O with strong catalytic oxidation ability in the aerobic alkaline solution,whereas the catalytic effect of the other product MnOOH is not *** the optimal reaction conditions of temperature 90℃,As/Mn molar ratio 12.74:1,air flow rate1.0 L/min,and stirring speed 300 r/min,As(Ⅲ) can be completely oxidized after 2 hr *** excellent catalytic oxidation ability of MnSO_(4)on As(Ⅲ) was mainly attributed to the indirect oxidation of As(Ⅲ) by the product Na_(0.55)Mn_(2)O_(4)·1.5H_(2)*** study shows a convenient and efficient process for the oxidation of As(Ⅲ) in alkali solutions,which has potential application value for the pre-oxidation of arsenic-containing solution or the detoxification of As(Ⅲ).

关键词： Arsenic Air oxidation Catalytic oxidation Manganese sulfate

Extracts from Huangqi(Radix Astragali Mongoliciplus) and Ezhu(Rhizoma Curcumae Phaeocaulis) inhibit Lewis lung carcinoma cell growth in a xenograft mouse model by impairing mitogen-activated protein kinase signaling, vascular endothelial growth factor prod

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Journal of Traditional Chinese Medicine 2019年第4期39卷 559-565页

作者： Xu chengyong Wang Yuguo Feng Jian Xu Ran Dou Yongqi Medical School of Chinese People's Liberation Army Chinese People's Liberation Army General HospitalBeijing 100853China Department of Traditional Chinese Medicine Hainan Branch of Chinese People's Liberation Army General HospitalSanyaHainan province 572013China Medical School of Chinese People's Liberation Army Chinese People's Liberation Army General HospitalBeijing 100853China Department of Traditional Chinese Medicine Chinese People's Liberation Army General HospitalBeijing 100853China

OBJECTIVE: To study the anti-tumor effects of the extracts from Huangqi(Radix Astragali Mongolici)and Ezhu(Rhizoma Curcumae Phaeocaulis) on the growth of Lewis lung carcinoma(LLC) in a xenograft mouse model and to investigate the possible underlying ***: LLC tumor-bearing C57 BL/6 mice were treated with normal saline, cisplatin(2 mg/kg intraperitoneally every other day), or Huangqi(Radix Astragali Mongolici) and Ezhu(Rhizoma Curcumae Phaeocaulis)(1∶1, 2∶1, or 3∶1 ratio;5, 8, or 11 g/kg crude drug intragastrically every day) for 15 *** weights and tumor volumes were measured every other day. Tumors were excised on day 15 and analyzed. Tumor microvessel density(MVD)was assessed by immunohistochemical staining of CD34;and expression of vascular endothelial cell growth factor(VEGF), the mitogen-activated protein kinases p38 mitogen-activated protein kinase(MAPK), extracellular signal-regulated kinases 1 and 2(ERK1/2), and Jun N-terminal kinase(JNK)and their phosphorylated forms were assessed by Western ***: Treatment with cisplatin caused a significant loss of body weight compared with controls,whereas Huangqi(Radix Astragali Mongolici) and Ezhu(Rhizoma Curcumae Phaeocaulis) extract combinations had no effect. Extracts from Huangqi(Radix Astragali Mongolici) and Ezhu(Rhizoma Curcumae Phaeocaulis) significantly decreased tumor weight and tumor MVD compared with controls,and at the 3∶1 treatment group had similar efficacy to cisplatin in reducing MVD. Tumors from Huangqi(Radix Astragali Mongolici) and Ezhu(Rhizoma Curcumae Phaeocaulis) treatments also showed decreased p38 MAPK, p-p38 MAPK, ERK1/2, p-ERK1/2,JNK, and p-JNK expression compared with the control group(all P he 2∶1 and 3∶1 treatment groups compared with the control group(P he xenograft mous

关键词： Carcinoma,Lewis lung Vascular endothelial cell growth factors Extracellular signal-regulated MAP kinases Angiogenesis Huangqi(Radix Astragali Mongolici) Ezhu(Rhizoma Curcumae Phaeocaulis)