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Effect of crystalline structure on terbuthylazine degradation by H_2O_2-assisted TiO_2 photocatalysis under visible irradiation

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Journal of Environmental Sciences 2019年第5期31卷 153-160页

作者： Jianjun Tang Yiqing chen Zijun dong Shenzhen Key Laboratory of Industrial Water Conservation and Municipal Wastewater Reclamation Technology Shenzhen Polytechnic

Various methods for shifting the optical response of TiO_2 into the visible(Vis) range have been reported. Herein, we reported the application of a TiO_2/H_2O_2/Vis process and the effects of TiO_2 crystalline structure on the degradation of terbuthylazine. The results indicated that TiO_2 crystalline structure and H_2O_2 addition had significant effects on terbuthylazine degradation: its degradation rate could be increased from 7% to 70% with H_2O_2 addition after 180 min of reaction, the synergistic degradation of terbuthylazine by TiO_(2-)Fe^(3+) was substantially accelerated, with the degradation rate reaching up to 100% after20 min of reaction, and rutile TiO_2 showed better photocatalytic activity and a more obvious synergistic effect than anatase TiO_2. The addition of free-radical scavengers(tert-butyl alcohol or methanol) inhibited the degradation efficiency of rutile TiO_2, but had a relatively minor effect on anatase TiO_2. Fluorescence spectrophotometry analysis indicated that hydroxyl free radicals could be continuously produced when using rutile TiO_2 as the photocatalyst. Degradation of terbuthylazine catalyzed by rutile TiO_2 occurred mainly in solution, but occurred on the particle surface of the photocatalyst when catalyzed by anatase TiO_2. This study provides new insight into the role of TiO_2 crystalline structure on the degradation of terbuthylazine and its photocatalytic degradation mechanism.

关键词： Visible-light photocatalysis Reaction pathway Hydroxyl free radical Hydrogen peroxide

Track-position and vibration control simulation for strut of the Stewart platform

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2013年第4期14卷 281-291页

作者： Zhao-dong XU chen-hui WENG MOE Key Laboratory of C&PC Structures Southeast University Guangzhou Design Institute

Vibrations inherently generated by on-board disturbance sources degrade the performance of the instruments in an on-orbit spacecraft,which have stringent accuracy *** Stewart platform enables both track-positioning and vibration *** strut of the Stewart platform is designed as a piezoelectric(PZT) element in series with a voice coil motor(VCM) element and a viscoelastic *** track-positioning system uses a VCM as the main positioning control driver and a PZT as the positioning *** vibration control system uses the characteristics of struts including active and passive control elements to attenuate the *** results indicate that the Stewart platform with the designed struts has good performance in tracking and vibration attenuation with different interference waves.

关键词： Stewart platform Track-positioning control Vibration control

Modeling of nonlinear dynamical systems based on deterministic learning and structural stability

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Science China(Information Sciences) 2016年第9期59卷 91-106页

作者： Danfeng chen Cong WANG Xunde dong School of Automation Science and Engineering South China University of Technology Guangdong Key Laboratory of Biomedical Engineering South China University of Technology School of Mathematical Sciences South China University of Technology

Recently, a deterministic learning(DL) theory was proposed for accurate identification of system dynamics for nonlinear dynamical systems. In this paper, we further investigate the problem of modeling or identification of the partial derivative of dynamics for dynamical systems. Firstly, based on the locally accurate identification of the unknown system dynamics via deterministic learning, the modeling of its partial derivative of dynamics along the periodic or periodic-like trajectory is obtained by using the mathematical concept of directional derivative. Then, with accurately identified system dynamics and the partial derivative of dynamics,a C1-norm modeling approach is proposed from the perspective of structural stability, which can be used for quantitatively measuring the topological similarities between different dynamical systems. This provides more incentives for further applications in the classification of dynamical systems and patterns, as well as the prediction of bifurcation and chaos. Simulation studies are included to demonstrate the effectiveness of this modeling approach.

关键词： system modeling system identification deterministic learning nonlinear dynamics structural sta bility topological equivalence

Environmental and technological effects on ancient social evolution at different spatial scales

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Science China Earth Sciences 2017年第12期60卷 2067-2077页

作者： dong GuangHui LIU FengWen chen FaHu MOE Key Laboratory of Western China's Environmental Systems(Ministry of Education) Lanzhou UniversityLanzhou 730000China

The rise and fall of ancient cultures and civilizations is a hotly debated topic that has generated disagreements and disputes. In this paper we summarize some case studies on the abandonment of ancient sites, the prosperity and collapse of ancient cultures, and demographic changes, as well as the influence of environment and technology during the prehistoric and historic periods. We then suggest that the dominant influencing factors for the evolution of ancient societies vary by spatial *** the local scale, sudden disasters are critical factors leading to the destruction and abandonment of large settlements. On a regional scale, climatic variations(e.g., droughts or cold events lasting for decades or centuries) are important factors that induce the collapse of ancient civilizations and mass migrations, while an enduring and stable optimal climate facilitated the prosperity of ancient civilizations. On a global scale, major technological innovations and their dispersion lasting for centuries and even millennia are major catalysts for population growth and social development. Lastly, we illustrate a possible mechanism under which environmental and technological factors played a critical role in ancient human survival and social evolution on different spatial scales.

关键词： Prehistoric period Historic period Man-land relationship Cultural evolution Sudden disaster Climatic variation Technological innovation

Scoping biology-inspired chemical engineering

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Chinese Journal of Chemical Engineering 2016年第1期24卷 1-8页

作者： Xiao dong chen Suzhou Key Laboratory of Green Chemical Engineering School of Chemical and Environmental Engineering College of ChemistryChemical Engineering and Material SciencesSoochow UniversitySuzhou 215000China

Biology is a rich source of great ideas that can inspire us to find successful ways to solve the challenging problems in engineering practices including those in the chemical industry. Bio-inspired chemical engineering(Bio Ch E)may be recognized as a significant branch of chemical engineering. It may consist of, but not limited to, the following three aspects: 1) Chemical engineering principles and unit operations in biological systems; 2) Process engineering principles for producing existing or developing new chemical products through living ‘devices';and 3) Chemical engineering processes and equipment that are designed and constructed through mimicking(does not have to reproduce one hundred percent) the biological systems including their physical–chemical and mechanical structures to deliver uniquely beneficial performances. This may also include the bio-inspired sensors for process monitoring. In this paper, the above aspects are defined and discussed which establishes the scope of BioChE.

关键词： Bioinspired chemical engineering Biology Chemical engineering Material science Multidisciplinary Multiscale Biomimic Bionic

Three Sclerotinia species as the cause of white mold on pea in Chongqing and Sichuan of China

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Journal of Integrative Agriculture 2021年第11期20卷 2957-2965页

作者： DENG dong SUN Su-li DU chen-zhang XIANG Chao LONG Jue-chen chen Wei-dong ZHU Zhen-dong Institute of Crop Sciences Chinese Academy of Agricultural SciencesBeijing 100081P.R.China Chongqing Academy of Agricultural Sciences Chongqing 402160P.R.China Crop Research Institute Sichuan Academy of Agricultural SciencesChengdu 610066P.R.China United States Department of Agriculture-Agricultural Research Service Washington State UniversityPullmanWA 99164USA

White mold of pea caused by Sclerotinia sclerotiorum is a common disease in ***,we discovered that the diverse Sclerotinia species could cause white mold on pea plants in Chongqing and Sichuan of China during recent disease ***,the objective of this study was to confirm the causal agents from diseased pea *** obtained isolates of white mold from Chongqing and Sichuan were identified by morphological characters and molecular characterization to determine the pathogen species,and their pathogenicity was confirmed on pea through completing Koch’s *** isolates of Sclerotinia-like were obtained from diseased plants or *** on morphological characteristics and molecular characterization,30 isolates were identified to three species,six isolates as ***,seven as ***,and 17 as *** pathogenicity tests on pea cultivars Zhongwan 4 and Longwan 1,all 30 isolates caused typical symptoms of white mold on the inoculated plants,and the inoculated pathogens were re-isolated from the diseased *** study confirmed that white mold of pea was caused by three Sclerotinia species,***,*** and *** in Chongqing and *** is the first report that *** and *** cause white mold of pea in Southwest China.

关键词： Pisum sativum white mold Sclerotinia sclerotiorum Sclerotinia minor Sclerotinia trifoliorum

Mechanical property and anisotropy of as-extruded Mg-Zn-Y-Mn alloys with different volume fraction of long-period stacking ordered(LPSO) phase

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Journal of Rare Earths 2024年第12期42卷 2259-2269页

作者： Dahui Liang Mincong chen Chuanqiang Li Zhipei Tong Yong dong dong Bian School of Materials and Energy Guangdong University of Technology Medical Research Institute Department of Orthopedics Guangdong Provincial People's Hospital (Guangdong Academy of Medical Sciences) Southern Medical University

Effects of different volume fraction of long-period stacking ordered(LPSO) phase on the microstructure,mechanical property and anisotropy of the as-extruded Mg-xZn-yY-0.1Mn(x = 1 wt%, 2 wt%, 4 wt% and y = 2 wt%, 4 wt%, 8 wt%) alloys were studied by an optical microscope, a scanning electron microscope,texture analysis, a transmission electron microscope and tensile testing. The results reveal that the volume fraction of LPSO phase increases from ZW12 to ZW24 to ZW48 alloys with the elevating Zn and Y content but constant Y/Zn value, and the mechanical strength of the LPSO-containing Mg-Zn-Y-Mn system is gradually improved when increasing LPSO phases. With the highest volume fraction of LPSO phase, ZW48 alloy presents the highest ultimate tensile strength(UTS) of 427 MPa along the extrusion direction(ED) when compared with those of ZW12 alloy with the UTS of 307 MPa and ZW24 alloy with the UTS of 347 MPa. Moreover, the elongation ratio of ZW48 alloy is maintained to moderate 9.9%, which is also the highest among three studied alloys. On the other hand, texture analysis demonstrates that the basal texture of the a-Mg phase in the ZW48 alloy is significantly weakened by the generation of more LPSO phases. On the contrary, a high texture intensity of a-Mg phase and obvious mechanical anisotropy can be observed for the ZW12 alloy. However, mechanical anisotropy still exists in the ZW48 alloy containing massive LPSO phases, which is attributed primarily to the zonal distribution of large LPSO along the ED.

关键词： Microstructure Mg-Zn-Y-Mn alloy LPSO phase Texture Mechanical anisotropy Rare earths

Numerical Investigation of the Thermal Response to Skin Tissue during Laser Lipolysis

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Journal of Thermal Science 2018年第5期27卷 470-478页

作者： chen Bin ZHANG Yue LI dong State Key Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong University

Laser lipolysis can effectively treat obesity and its associated diseases, such as hypertension, fatty liver, and hyperlipidemia. However, currently available invasive laser lipolysis, which transmits laser to a fiber-optic catheter inserted into the subcutaneous tissue for irradiation through an incision, may cause hematomas, infections, and empyrosis. The current study presents a novel, noninvasive approach for laser lipolysis, which directly irradiates the intact skin surface without an incision and preferentially targets adipose tissue at the near-infrared band. High laser energy is necessary to damage adipocytes; however, this may carbonate and burn the dermis. Therefore, the introduction of skin cooling is essential to avoid unwanted hyperthermal injury and improve the threshold of radiant exposure. In the current study, we investigated a novel noninvasive approach assisted with skin cooling by establishing a homogeneous multi-layer skin model. In this method, light propagation in the skin was simulated by using the Monte Carlo method. Skin cooling was employed before laser irradiation to protect the epidermis from thermal damage, which was treated as a boundary condition based on Newton's law. The numerical results showed that the photons were deposited in the adipose layer more than in the other layers. Laser can effectively destroy adipose tissue at an energy density of >200 J/cm^2 at 1210 nm wavelength, whereas at least 300 J/cm^2 is required at 1064 nm to achieve the same effect. In this experiment, at >5 s pulse width, the selectivity of adipose was not obvious. Moreover, the results indicated that 60 ms R134a or R404a spray can effectively reduce the temperature of the epidermis. R404a exhibited a stronger cooling effect than R134a. Cold air cooling at -10 °C for 10 s could effectively decrease the skin temperature, and deeper cooling could be achieved by cold air cooling compared with cryogen spray cooling.

关键词： laser lipolysis Nd:YAG laser multi-layer skin model skin cooling

Rate-distortion weighted SPIHT algorithm for interferometer data processing

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Journal of Systems Engineering and Electronics 2011年第4期22卷 547-556页

作者： Jing Ma Jindong Fei dong chen Science and Technology on Space Systems Simulation Laboratory Beijing Simulation Center Beijing 100854 E R. China Institute of Telecommunication Satellite China Academy of Space Technology Beijing 100094 P. R. China

As one of the next generation imaging spectrometers, the interferential spectrometer （iS） possesses the advantages of high throughput, multi-channel and great resolution. The data of IS are produced in the spatial domain, but optical applications are in the Fourier domain. Traditional compression methods can only protect the visual quality of interferometer data in the spatial do- main but ignore the distortion in the Fourier domain. The relation between the distortion in the Fourier domain and the compression in the spatial domain is analyzed. By mathematical proof and val- idation with experiments, the relation between spatial and Fourier domains is discovered, and the significance in the Fourier domain is more important as optical path difference （OPD） increasing in the spatial domain. Based on this relation, a novel coding scheme is proposed, which can compress data in the spatial domain while reducing the distortion in the Fourier domain. In this scheme, the bit stream of the set partitioning in hierarchical trees （SPIHT） is truncated by adaptively lifting rate-distortion slopes according to the priorities of OPD based on rate-distortion optimization theory. Experimental results show that the proposed method can provide better protection of spectrum curves in the Fourier domain while maintaining a comparable visual quality in the spatial domain.

关键词： interferential spectrometer (IS) multi-spectrum compression set partitioning in hierarchical trees (SPIHT).