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Thermal stability improvement of sprayable fast-responding pressure-sensitive paint for measurement above 100℃

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Chinese Journal of Aeronautics 2021年第1期34卷 320-326页

作者： di peng Feng GU Zhe ZHONG Yingzheng LIU Key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai 200240China

The thermal stability of sprayable fast-responding Pressure-Sensitive Paint(fast PSP)was investigated to explore the possibility for application in turbomachinery and hypersonic research with temperature above 100℃.The first part of the study focused on a widely-used Polymer Ceramic PSP(PC-PSP).The effects of thermal degradation on its key sensing properties,including luminescent intensity,pressure sensitivity and response time,were examined for a temperature range from 60 to 100℃.Severe degradation in intensity and pressure sensitivity was found as temperature reached 70℃or higher,which would cause failure of PSP application in these ***,a fast-responding Mesoporous-Particle PSP(MP-PSP)was developed which did not show degradation effects until 140℃.The greatly improved thermal stability of MP-PSP was attributed to:selection of polymer with higher glass transition temperature(polystyrene)to delay the saturation effect of oxygen quenching as temperature increased;porous and hollow structure of particles for luminophore deposition that minimizes polymer–luminophore *** new paint formulation has significantly raised the upper temperature limit of fast PSP and offers more opportunities for applications in harsh environment.

关键词： Dynamic response Polymer–luminophore interaction Pressure sensitivity Pressure-sensitive paint Thermal degradation

Study of probability integration method parameter inversion by the genetic algorithm

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International Journal of Mining Science and Technology 2017年第6期27卷 1073-1079页

作者： Li Peixian peng di Tan Zhixiang Deng Kazhong College of Geoscience and Surveying Engineering China University of Mining and Technology (Beijing) School of Environment Science and Spatial Informatics China University of Mining and Technology

In order to obtain accurate probability integration method(PIM) parameters for surface movement of multi-panel mining, a genetic algorithm(GA) was used to optimize the parameters. As the measured surface movement is affected by more than one mining panel, traditional PIM parameter inversion model is difficult to ensure the reliability of the results due to the complexity of rock movement. With crossover,mutation and selection operators, GA can perform a global optimization search and has high computation efficiency. Compared with the pattern search algorithm, the fitness function can avoid falling into local minima traps. GA reduces the risk of local minima traps which improves the accuracy and reliability with the mutation mechanism. Application at Xuehu colliery shows that GA can be used to inverse the PIM parameters for multi-panel surface movement observation, and reliable results can be obtained. The research provides a new way for back-analysis of PIM parameters for mining subsidence under complex conditions.

关键词： Probability integration method GA Mining subsidence Parameter inversion Multiobjective optimization

Cultivar-dependent rhizobacteria community and cadmium accumulation in rice: Effects on cadmium availability in soils and iron-plaque formation

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Journal of Environmental Sciences 2022年第6期34卷 90-102页

作者： Feng Zhang di peng Lu Liu Huidan Jiang Lianyang Bai Longping Branch Graduate School of Hunan UniversityChangsha 410125China Biotechnology Research Institute Hunan Academy of Agricultural SciencesChangsha 410125China

The association between the rhizospheric microbial community and Cd accumulation in rice is poorly understood.A field trial was conducted to investigate the different rhizobacterial communities of two rice cultivars with high Cd accumulation(HA)and low Cd accumulation(LA)at four growth *** showed that the Cd content in the roots of the HA cultivar was 1.23-27.53 higher than that of the LA cultivar(0.08-10.5μg/plant)at four *** LA cultivar had a significantly lower Cd availability in rhizosphere and a higher quantity of iron plaque(IP)on the root surface than the HA cultivar at four *** resulted in the reduction of Cd concentration in IPs and Cd translocation from *** analysis indicated that the LA cultivar formed a distinct rhizobacterial community from the HA cultivar and had lessα-*** rhizosphere of the LA cultivar was enriched in specific bacterial taxa(e.g.,Massilia and Bacillus)involved in Cd immobilization by phosphate precipitation and IP formation by iron ***,the rhizosphere in the HA cultivar assembled abundant sulfur-oxidizing bacteria(e.g.,Sulfuricurvum)and iron reduction bacteria(Geobacter).They promoted Cd mobilization and reduced IP formation via the metal redox *** study reveals a potential approach in which specific rhizobacteria decrease or increase Cd accumulation in rice on contaminated soil and provides a new perspective for secure rice production.

关键词： Rice cultivar Cd accumulation Rhizosphere Bacterial community Iron plaque Cd availability

Numerical Investigation of the Angle of Attack Effect on Cloud Cavitation Flow around a Clark-Y Hydrofoil

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Computer Modeling in Engineering & Sciences 2024年第6期139卷 2947-2964页

作者： di peng Guoqing Chen Jiale Yan Shiping Wang College of Engineering Peking UniversityBeijing100871China College of Shipbuilding Engineering Harbin Engineering UniversityHarbin150001China

Cavitation is a prevalent phenomenon within the domain of ship and ocean engineering,predominantly occurring in the tail flow fields of high-speed rotating propellers and on the surfaces of high-speed underwater *** re-entrant jet and compression wave resulting from the collapse of cavity vapour are pivotal factors contributing to cavity ***,these phenomena significantly modulate the evolution of cavitation *** this paper,numerical investigations into cloud cavitation over a Clark-Y hydrofoil were conducted,utilizing the Large Eddy Simulation(LES)turbulence model and the Volume of Fluid(VOF)method within the OpenFOAM *** analysis of results obtained at different angles of attack is undertaken.A discernible augmentation in cavity thickness is observed concomitant with the escalation in attack angle,alongside a progressive intensification in pressure at the leading edge of the hydrofoil,contributing to the suction *** results can serve as a fundamental point of reference for gaining a deeper comprehension of cloud cavitation dynamics.

关键词： Cloud cavitation re-entrant jet compression wave clark-Y hydrofoil

Study on Acoustic Modeling in a Mandarin Continuous Speech Recognition

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Journal of China University of Mining and Technology 2007年第1期17卷 143-146页

作者： peng di LIU Gang GUO Jun School of Information Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

The design of acoustic models is of vital importance to build a reliable connection between acoustic wave-form and linguistic messages in terms of individual speech units. According to the characteristic of Chinese phonemes, the base acoustic phoneme units set is decided and refined and a decision tree based state tying approach is explored. Since one of the advantages of top-down tying method is flexibility in maintaining a balance between model accuracy and complexity, relevant adjustments are conducted, such as the stopping criterion of decision tree node splitting, during which optimal thresholds are captured. Better results are achieved in improving acoustic modeling accuracy as well as minimizing the scale of the model to a trainable extent.

关键词： acoustic model base acoustic phoneme units decision tree

Comparison of membrane fouling during short-term filtration of aerobic granular sludge and activated sludge

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Journal of Environmental Sciences 2007年第11期19卷 1281-1286页

作者： ZHOU Jun YANG Feng-lin MENG Fan-gang AN peng WANG di School of Environmental and Biological Science and Technology Dalian University of Technology Dalian 116024 China

Aerobic granular sludge was cultivated adopting internal-circulate sequencing batch airlift reactor. The contradistinctive experiment about short-term membrane fouling between aerobic granular sludge system and activated sludge system were investigated. The membrane foulants was also characterized by Fourier transform infrared （FTIR） spectroscopy technique. The results showed that the aerobic granular sludge had excellent denitrification ability; the removal efficiency of TN could reach 90%. The aerobic granular sludge could alleviate membrane fouling effectively. The steady membrane flux of aerobic granular sludge was twice as much as that of activated sludge system. In addition, it was found that the aerobic granular sludge could result in severe membrane pore-blocking, however, the activated sludge could cause severe cake fouling. The major components of the foulants were identified as comprising of proteins and polysaccharide materials.

关键词： membrane bioreactor membrane fouling pore-blocking cake layer resistance aerobic granular sludge

Novel Shaped Sweeping Jet for Improved Film Cooling and Anti-Deposition Performance

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Journal of Thermal Science 2024年第6期33卷 2089-2096页

作者： ZHOU Wenwu WANG Kechen ZHANG Tianluan WEN Xin peng di LIU Yingzheng Key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai 200240China

The present study proposed a shaped sweeping jet(SJ)that possesses the merits of both SJ and shaped hole,which demonstrates significantly improved cooling effectiveness and anti-deposition *** to a classical 777 shaped hole,the shaped SJ exhibits a maximum enhancement of 70%in cooling effectiveness and a maximum reduction of 28%in particle deposition height,*** to the periodic oscillation of coolant jet and higher streamwise jet momentum,the shaped SJ can provide much wider coolant coverage and therefore sweep the adhesive particle away from the *** study is the first attempt to reconcile the performance of film cooling and particle anti-deposition simultaneously,which offers a promising design concept for future engine cooling.

关键词： sweeping jet film cooling particle deposition pressure sensitive paint multi-perspective scanni

Improved Turbine Vane Endwall Film Cooling by Using Sand-Dune-Inspired Design

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Journal of Thermal Science 2022年第3期31卷 958-973页

作者： ZHOU Wenwu SHAO Hongyi QENAWY Mohamed peng di HU Hui LIU Yingzheng Key Lab of Education Ministry for Power Machinery and Engineering School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai200240China Gas Turbine Research Institute Shanghai Jiao Tong UniversityShanghai200240China Department of Aerospace Engineering Iowa State UniversityAmesIA50011USA

As continuous of the previous sand-dune-inspired design,the Barchan-Dune-Shaped Injection Compound(BDSIC)’s film cooling performance at the endwall region was further investigated both experimentally and *** the public 777-shaped hole was served as a baseline,the BDSIC’s endwall effectiveness was assessed at various blowing *** were performed in a single-passage transonic wind tunnel using pressure-sensitive paint(PSP)*** dioxide was used as coolant with density ratio of DR=*** purge slot’s blowing ratio was fixed at M=0.3,but the coolant holes were adjusted within M=0.5–*** measured experimental results indicate that the film distribution at the endwall is strongly affected by the passage flow *** BDSIC holes demonstrate much higher film effectiveness than the 777-shaped holes for all blowing ratios,~30%enhancement for regionally averaged effectiveness at M=1.0 and~26%at M=*** shown by the numerical results,the existence of BDSIC reduced the coolant penetration effect at a higher blowing *** was deflected and its momentum increased in the streamwise direction,therefore providing more robust film coverage over the endwall *** anti-counter-rotating vortex pair induced by the BDSIC further stabilized the coolant film and increased the coolant spreading downstream.

关键词： endwall film cooling pressure-sensitive paint Barchan dune 777-shaped hole counter-rotating vortex

Evaluation of Government Performance in Haze Pollution Control and the Optimization Path in Beijing

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Chinese Journal of Urban and Environmental Studies 2020年第3期8卷 44-62页

作者： LI Yunyan SUN Guihua di peng School of Economics and Management Beijing University of Technology

In recent years, Beijing has been more often confronted with serious haze pollution, especially in autumn and winter. The People’s Government of Beijing Municipality has adopted a package of measures to control the haze pollution with its best efforts. To objectively evaluate how effective these haze pollution control measures are from different perspectives and in an all-round way, it is necessary to adopt a scientific and reasonable approach. Based on the Balanced Scorecard(BSC)idea, we establish a system of indexes to evaluate the government performance of Beijing in haze pollution control from the four perspectives of development quality, public services, government management and development potential, and use a combination of analytic hierarchy process(AHP) and entropy weight method(EWM) to determine the index weights, and objectively evaluate Beijing’s performance in haze pollution control from 2010 to 2016. The results show that the scores for the four perspectives are all on the rise, and since the implementation of the Air Pollution Prevention and Control Action Plan in 2013, the government’s haze pollution control measures have achieved significant results, and made a much higher overall score. On that basis,we propose the optimized path for Beijing’s haze pollution control, namely, accelerating the upgrading of development quality, improving the public services level, strengthening the government management, tapping the development potential of haze pollution control and increasing the linkage and cooperation between the governments of Beijing, Tianjin and Hebei.

关键词： Haze pollution control government performance evaluation Balanced Scorecard Beijing. 1. Introduction