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| 1 | Bifurcation and Chaos Analysis of Nonlinear Rotor System with Axial-grooved Gas-lubricated Journal Bearing Support显示文摘Axial-grooved gas-lubricated journal bearings have been widely applied to precision instrument due to their high accuracy, low friction, low noise and high stability. The rotor system with axial-grooved gas-lubricated journal bearing support is a typical nonlinear dynamic system. The nonlinear analysis measures have to be adopted to analyze the behaviors of the axial-grooved gas-lubricated journal bearing-rotor nonlinear system as the linear analysis measures fail. The bifurcation and chaos of nonlinear rotor system with three axial-grooved gas-lubricated journal bearing support are investigated by nonlinear dynamics theory. A time-dependent mathematical model is established to describe the pressure distribution in the axial-grooved compressible gas-lubricated journal bearing. The time-dependent compressible gas-lubricated Reynolds equation is solved by the differential transformation method. The gyroscopic effect of the rotor supported by gas-lubricated journal bearing with three axial grooves is taken into consideration in the model of the system, and the dynamic equation of motion is calculated by the modified Wilson-θ-based method. To analyze the unbalanced responses of the rotor system supported by finite length gas-lubricated journal bearings, such as bifurcation and chaos, the bifurcation diagram, the orbit diagram, the Poincaré map, the time series and the frequency spectrum are employed. The numerical results reveal that the nonlinear gas film forces have a significant influence on the stability of rotor system and there are the rich nonlinear phenomena, such as the periodic, period-doubling, quasi-periodic, period-4 and chaotic motion, and so on. The proposed models and numerical results can provide a theoretical direction to the design of axial-grooved gas-lubricated journal bearing-rotor system. | ZHANG Yongfang HEI Di Lü Yanjun WANG Quandai MüLLER Norbert | 2014 | Chinese Journal of Mechanical Engineering2014，27，2： | 9 |
| 2 | Self-immolative micellar drug delivery:The linker matters显示文摘Redox-responsive polymer-drug conjugate micelles are excellent nanoscale vehicles for self-immolative intracellular drug delivery.To covalently connect the polymer and drug,disulfide-bearing linkers,such as 3,3'-dithiodipropionic acid (DDPA) and 4,4'-dithiodibutyric add (DDBA),are used.In this paper,we report the influence of linker length on the therapeutic outcome of redox-sensitive conjugate micelles.Curcumin was selected as the model drug and it was conjugated to a multivalent methoxy poly(ethylene glycol)-polylysine copolymer with DDPA or DDBA as the linker.The obtained two polymer-curcumin conjugates were amphiphilic and could self-assemble into micelles that have a hydrodynamic diameter less than 100 nm.The loading of curcumin in both micelles was above 20% (w/w).Irrespective of the linker type,micelle disassembly was observed due to the collapse of the disulfide bond in a reducing environment.However,the rate of curcumin release was much faster with the DDBA linker than with the DDPA linker as the side product was a 5-membered ring with a low ring strain.The linker length-induced variation of curcumin release kinetics caused a significant difference in the intracellular drug concentration and a higher cytotoxicity was witnessed in three model cell lines (HeLa,PC3,and 4T1) for the micelles with a DDBA linker compared to those containing a DDPA linker.As expected,this phenomenon was also observed in HeLa tumor-bearing nude mice in vivo.The current work highlights the significance of linker length in engineering redox-responsive on-demand delivery systems. | Xuan Meng Min Gao Jian Deng Di Lu Aiping Fan Dan Ding Deling Kong Zheng Wang Yanjun Zhao | 2018 | Nano Research2018，11，12： | 2 |
| 3 | Stability and bi- furcation of a non-linear bearing-flexible rotor coupling dynamic system显示文摘 | Lu Yanjun Dai Rong Hei Di | 2009 | IMechE Journal of Mechanical En- gineering Science2009，223，4： | 1 |
| 4 | MFCC-based perceptual hashing for compressed domain of speech content i- dentification 显示文摘 | Zhang Qiuyu Liu Yangwei Di Yanjun | 2014 | Journal of Chemical and Pharmaceutical Research2014，6，7： | 1 |
| 5 | Stability and bifurcation of a non-linear bearing-flexible rotor coupling dynamic system显示文摘 | Lu Yanjun Dai Rong Hei Di | 2009 | Journal of Mechanical Engineering Science2009，223，4： | 1 |
| 6 | Retrogradation behaviour of high-amylose rice starch prepared by improved extrusion cooking technology显示文摘 | Yanjun Zhang Wei Liu Chengmei Liu Shunjing Luo Ti Li Yunfei Liu Di Wu Yanna Zuo | 2014 | Food Chemistry2014，，： | 1 |
| 7 | Stability and bifurcation of nonlinear bearing-flexible rotor coupling dynamic system显示文摘 | LU Yanjun DAr Rong HEr Di | 2009 | IMechE Part C: Journal of Mechanical Engineering Science2009，223，4： | 1 |
| 8 | An Objective Approach to Generating Multi-Physics Ensemble Precipitation Forecasts Based on the WRF Model显示文摘Selecting proper parameterization scheme combinations for a particular application is of great interest to the Weather Research and Forecasting(WRF)model users.This study aims to develop an objective method for identifying a set of scheme combinations to form a multi-physics ensemble suitable for short-range precipitation forecasting in the Greater Beijing area.The ensemble is created by using statistical techniques and some heuristics.An initial sample of 90 scheme combinations was first generated by using Latin hypercube sampling(LHS).Then,after several rounds of screening,a final ensemble of 40 combinations were chosen.The ensemble forecasts generated for both the training and verification cases using these combinations were evaluated based on several verification metrics,including threat score(TS),Brier score(BS),relative operating characteristics(ROC),and ranked probability score(RPS).The results show that TS of the final ensemble improved by 9%-33%over that of the initial ensemble.The reliability was improved for rain≤10 mm day^-1,but decreased slightly for rain>10 mm day^-1 due to insufficient samples.The resolution remained about the same.The final ensemble forecasts were better than that generated from randomly sampled scheme combinations.These results suggest that the proposed approach is an effective way to select a multi-physics ensemble for generating accurate and reliable forecasts. | Chenwei SHEN Qingyun DUAN Wei GONG Yanjun GAN Zhenhua DI Chen WANG Shiguang MIAO | 2020 | Journal of Meteorological Research2020，34，3： | 0 |
| 9 | Release behavior of soluble salts in MSWI bottom ash used as road basement materials under continuous rainfall conditions显示文摘The bottom ash is increasingly used as a substitute aggregate material in road construction in China,and road salting is the major salt source in groundwater.Continuous rainfall releases soluble salts from the bottom ash subgrade into the surrounding soil and groundwater,resulting in potential hazards.Different methods were employed to simulate and collect runoff water during rainfall events,including batch leaching test,dynamic leaching test and constant head test,to assess environmental impact of bottom ash as road basement materials under continuous rainfall conditions.This study simulated the seepage of bottom ash backfill roads under different rainfall intensities,rainfall times,and rainfall pH values.A comprehensive sampling and laboratory testing program was undertaken to characterize the environmental impact of soluble salts from bottom ash.The obtained results reveal that the leaching concentrations of Cl^(−)and SO_(4)^(2−)exceed the limit specified in the class V standard of surface water,which are 2.06–2.17 times and 1.08–1.25 times,respectively.By examining the long-term environmental influence under the condition of continuous rainfall,the leaching of Cl^(−)mainly occurs in the early leaching stage,and the maximum leaching concentration reaches 19,700 mg/L.The release concentration of Cl^(−)begins to be lower than the class V standard of surface water when continuous rainfall approaches the total rainfall for 13 months.The cumulative release of Cl^(−)in the bottom ash is 2.8–5.4 mg/g.Both rainfall intensity and rain pH affect the release of Cl^(−).The obtained results derived from the constant head tests indicate that stagnant water caused by rainfall deteriorates the release of soluble salt into the groundwater in only 1 day,especially at the early stage of 12 h.This work provides some basic information about how to minimize damage to the surrounding environment caused by the leaching of salt in bottom ash. | Lingqin Zhao Dongming Zhang Yanjun Hu Qianqian Guo Long Jiao Nan Zhou Francesco Di Maio | 2023 | Waste Disposal and Sustainable Energy2023，5，4： | 0 |
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