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Hy.raulic resistance of river ice jams

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Journal of Hy.rody.amics 2019年第3期31卷 504-511页

作者： Lin Fan Ze-y. Mao Hung Tao Shen Department of Hy.raulic Engineering Tsinghua University Beijing 100084 China Development Research Center of the Ministry.of Water Resources Beijing 100036 China Department of Civil and Environmental Engineering Clarkson University Potsdam NY 13676 USA

The hy.raulic resistance of the river ice jams consists of the resistances due to the seepage flow through the jam and the shear stress on the undersurface of the jam. Existing empirical formulations consider only.the the undersurface resistance of the jam, and come up with relations between the jam resistance and the jam thickness with very.slight theoretical basis. Based on the analy.is of the seepage flow resistance and the flow resistance of the undersurface of the jam, it is shown that the resistance due to the seepage flow is a dominating part of the jam resistance, except for the portion of the jam where the thickness is very.small. This analy.is also shows that the total jam resistance can be approximated by.a linear function of the jam thickness or the ratio of the jam thickness to the flow depth under the jam.

关键词： River ice hy.raulic resistance ice jam friction factor Manning's coefficient

Capillary.effect-based selective sealing strategy.for increasing piezoelectric MEMS speaker performance

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Microsy.tems & Nanoengineering 2024年第4期10卷 329-341页

作者： y.n Wang Tunan Lv Junning Zhang Hongbin y. School of Optical and Electronic Information Huazhong University of Science and TechnologyWuhan 430074China Optics Valley.Laboratory WuhanHubei 430074China Wuhan National Laboratory.for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China

To address the serious acoustic performance deterioration induced by.air leakage in the low-frequency.range and the asy.chronous vibration in electroacoustic transduction structures near the resonant frequency.a novel sealing strategy.is proposed that targets one of the most widely.reported piezoelectric MEMS speaker *** design consists of multiple cantilever beams,in which the air gaps between cantilevers are automatically.and selectively.filled with liquid poly.imethy.siloxane(PDMS)via the capillary.effect,followed by.*** the proof-of-concept demonstration,the sound pressure level(SPL)within the frequency.range lower than 100 Hz markedly.increased after sealing in an experiment using an IEC ear ***,the SPL is increased by.4.9 dB at 20 Hz for a 40 Vpp driving ***,the deteriorated SPL response near the resonant frequencies of the cantilever beams(18 kHz–19 kHz)caused by.their asy.chronous vibration induced by.the fabrication process nonuniformity.also significantly.improved,which successfully.increased the SPL to approximately.17.5 ***,sealed devices feature nearly.the same SPL response as the initial counterpart in the frequency.band from 100 Hz to 16 kHz and a total harmonic distortion(THD)of 0.728%at 1 kHz for a 40 Vpp driving *** with existing sealing methods,the current approach offers easy.operation,low damage risk,excellent repeatability.reliability.and excellent robustness advantages and provides a promising technical solution for MEMS acoustic devices.

关键词： sealing piezoelectric effect

Ni nanoparticles supported on carbon as efficient cataly.ts for steam reforming of toluene(model tar)

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Chinese Journal of Chemical Engineering 2018年第2期26卷 322-329页

作者： Chun Shen Wuqing Zhou Hao y. Le Du Beijing Key.Laboratory.of Bioprocess College of Life Science and TechnologyBeijing University of Chemical Technology The State Key.Laboratory.of Chemical Resource Engineering Beijing Key Laboratory of Membrane Science and TechnologyBeijing University of Chemical Technology

This paper investigated the influences of surface properties of carbon support and nickel precursors(nickel nitrate, nickel chloride and nickel acetate) on Ni nanoparticle sizes and cataly.ic performances for steam reforming of toluene. Treatment with nitric acid helped to increase the amount of functional groups on the surface and hy.rophilic nature of carbon support, leading to a homogeneous distribution of Ni nanoparticles. The thermal decomposition products of nickel precursor also play.d an important role, Ni nanoparticles supported on carbon treated with acid using nickel nitrate as the precursor exhibited the smallest mean diameter of 4.5 nm. With the loading amount increased from 6 wt% to 18 wt%, the mean particle size of Ni nanoparticles varied from4.5 nm to 9.1 nm. The as-prepared cataly.t showed a high cataly.ic activity.and a good stability.for toluene steam reforming: 98.1% conversion of toluene was obtained with the Ni content of 12 wt% and the S/C ratio of3, and the conversion only.decreased to 92.0% after 700 min. Because of the high activity. good stability. and low cost, the as-prepared cataly.t opens up new opportunities for tar removing.

关键词： Ni nanoparticles Steam reforming Tar removing Cataly.ic performance

iGraph： an incremental data processing sy.tem for dy.amic graph

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Frontiers of Computer Science 2016年第3期10卷 462-476页

作者： Wuy.ng JU Jianxin LI Weiren y. Richong ZHANG School of Computer Science and Engineering Beihang University Beijing 100191 China

With the popularity.of social network, the de- mand for real-time processing of graph data is increasing. However, most of the existing graph sy.tems adopt a batch processing mode, therefore the overhead of maintaining and processing of dy.amic graph is significantly.high. In this pa- per, we design iGraph, an incremental graph processing sy.- tem for dy.amic graph with its continuous updates. The con- tribufions of iGraph include： 1） a hash-based graph partition strategy.to enable fine-grained graph updates; 2） a vertex- based graph computing model to support incremental data processing; 3） detection and rebalance methods of hotspot to address the workload imbalance problem during incre- mental processing. Through the general-purpose API, iGraph can be used to implement various graph processing algo- rithms such as PageRank. We have implemented iGraph on Apache Spark, and experimental results show that for real life datasets, iGraph outperforms the original GraphX in respect of graph update and graph computation.

关键词： big data distributed sy.tem in-memory.computing graph processing hotspot detection

INTEGRATION OF NON-UNIFORM RATIONAL B-SPLINES GEOMETRy.AND RATIONAL ABSOLUTE NODAL COORDINATES FORMULATION FINITE ELEMENT ANALy.IS

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Acta Mechanica Solida Sinica 2014年第5期27卷 486-495页

作者： Peng Lan Zuqing y. Liang Du Nianli Lu School of Mechatronic Engineering Harbin Institute of Technology

This investigation is intended to develop a computer procedure for the integration of NURBS geometry.and the rational absolute nodal coordinate formulation （RANCF） finite element analy.is. A linear transformation is given that can be used to convert the NURBS curve to RANCF cable element mesh retaining the same geometry.and the same degree of continuity. including the discussion of continuity.control and mesh refinement. The green strain tensor is used to establish the nonlinear dy.amic equations with numerical examples to demonstrate the use of the procedure in the dy.amic analy.is of flexible bodies.

关键词： finite element method rational absolute nodal coordinate formulation (RANCF),NURBS mesh refinement

Cross Project Defect Prediction via Balanced Distribution Adaptation Based Transfer Learning

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Journal of Computer Science & Technology 2019年第5期34卷 1039-1062页

作者： Zhou Xu Shuai Pang Tao Zhang Xia-Pu Luo Jin Liu y.-Tian Tang Xiao y. Lei Xue College of Computer Science and Technology Harbin Engineering UniversityHarbin 150001China School of Computer Science Wuhan UniversityWuhan 430072China Department of Computing The Hong Kong Polytechnic UniversityHong Kong 999077China Department of ComputingThe Hong Kong Polytechnic UniversityHong Kong 999077China Key.Laboratory.of Network Assessment Technology Institute of Information EngineeringChinese Academy of Sciences Beijing 100190China Guangxi Key.Laboratory.of Trusted Software Guilin University of Electronic TechnologyGuilin 541004China Department of Computer Science City University of Hong KongHong Kong 999077China

Defect prediction assists the rational allocation of testing resources by.detecting the potentially.defective software modules before releasing products. When a project has no historical labeled defect data, cross project defect prediction (CPDP) is an alternative technique for this scenario. CPDP utilizes labeled defect data of an external project to construct a classification model to predict the module labels of the current project. Transfer learning based CPDP methods are the current mainstream. In general, such methods aim to minimize the distribution differences between the data of the two projects. However, previous methods mainly.focus on the marginal distribution difference but ignore the conditional distribution difference, which will lead to unsatisfactory.performance. In this work, we use a novel balanced distribution adaptation (BDA) based transfer learning method to narrow this gap. BDA simultaneously.considers the two kinds of distribution differences and adaptively.assigns different weights to them. To evaluate the effectiveness of BDA for CPDP performance, we conduct experiments on 18 projects from four datasets using six indicators (i.e., F-measure, g-means, Balance, AUC, EARecall, and EAF-measure). Compared with 12 baseline methods, BDA achieves average improvements of 23.8%, 12.5%, 11.5%, 4.7%, 34.2%, and 33.7% in terms of the six indicators respectively.over four datasets.

关键词： cross-project defect prediction transfer learning balancing distribution effort-aware indicator

THE POWER-LAW BEHAVIOUR OF AC RESPONSE OF INTERFACE: A FRACTAL TIME STOCHASTIC PROCESS

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Chinese Phy.ics Letters 1989年第6期6卷 273-276页

作者： y. Wenhai DING y. University.of Science and Technology.of China Hefei

A fractal time stochastic process of ion's motion in the interface is *** model can result in the universal power-law characteristics of interface.

关键词： fractal law interface.

Acidogenic sludge fermentation to recover soluble organics as the carbon source for denitrification in wastewater treatment： Comparison of sludge ty.es

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Frontiers of Environmental Science & Engineering 2018年第4期12卷 25-32页

作者： Lin Lin y.ng-y. Li Xiao-y.n Li Environmental Engineering Research Centre Departmelt of Civil Engineering The University of Hong Kong Pokfulam Hong Kong China Shenzhen Engineering Research Laboratory.for Sludge and Food Waste Treatment and Resource Recovery Graduate School at Shenzhcn Tsinghua University Shcnzhen 518055 China＊

For biological nitrogen （N） removal from wastewater, a sufficient organic carbon source is requested fbr denitrification. However. the organic carbon/nitrogen ratio in municipal wastcwatcr is becoming lower in recent y.ars, which increases the demand for the addition of external organic carbon, e.g. methanol, in wastewater treatment. The volatile fatty.acids （VFAs） produced by.acidogenic fenncntation of sewage sludge can be an attractive alternative for methanol. Chemically.enhanced primary.sedimentation （CEPS} is an effective process that applies chemical coagulants to enhance the removal of organic pollutants and phosphorus from wastewater by.sedimentation. In temls of the chemical and biological characteristics, the CEPS sludge is considerably.different from the conventional primary.and secondary.sludge. In the present study. FeCI3 and PACI （poly.lunfinum chloride） were used as the coagulants for CEPS treatment of raw sewage. The derived CEPS sludge （Fe-sludge and Al-sludge） was then processed with mcsophilic acidogenic fennentation to hy.roly.c the solid organics and produce VFAs for organic carbon recovery. and the sludge acidogenesis efficiency.was compared with that of the conventional primary.sludge and secondary.sludge. The results showed that the Fe-sludge exhibited the highest hy.roly.is and acidogenesis efficiency. while the Al-sludge and secondary. sludge had lower hy.roly.is efficiency.than that of primary.sludge. Utilizing ffie Fc-sludgc fermentation liquid as tbc carbon source for denitrificatiom more than 99%of nitrate removal was achieved in the main-stream wastewater treatment without any.external carbon addition, instead of 35% obtained from the conventional process of primary.sedimentation followed by.the oxic/anoxic （O/A） treatment.

关键词： Sewage sludge Chemically.enhanced primary.sedimentation(CEPS) Acidogenic fermentation Organic carbon recovery Nitrogen removal

Economic Design of  & S Control Charts Based on Taguchi's Loss Function and Its Optimization

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Chinese Journal of Mechanical Engineering 2012年第3期25卷 576-586页

作者： GUO y. y.NG Wen'an LIAO Wenhe GAO Shiwen College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210013China China Aerospace of Science and Technology.Corporation Beijing 100037China

Much research effort has been devoted to economic design of X ＆ S control charts,however,there are some problems in usual *** the one hand,it is difficult to estimate the relationship between costs and other model parameters,so the economic design method is often not effective in producing charts that can quickly.detect small shifts before substantial losses occur;on the other hand,in many.cases,only.one ty.e of process shift or only.one pair of process shifts are taken into consideration,which may.not correctly.reflect the actual process *** improve the behavior of economic design of control chart,a cost ＆ loss model with Taguchi＇s loss function for the economic design of X ＆ S control charts is embellished,which is regarded as an optimization problem with multiple statistical *** optimization design is also carried out based on a number of combinations of process shifts collected from the field operation of the conventional control charts,thus more hidden information about the shift combinations is mined and employ.d to the optimization design of control *** the same time,an improved particle swarm optimization（IPSO） is developed to solve such an optimization problem in design of X ＆ S control charts,IPSO is first tested for several benchmark problems from the literature and evaluated with standard performance *** results show that the proposed algorithm has significant advantages on obtaining the optimal design parameters of the *** proposed method can substantially.reduce the total cost（or loss） of the control charts,and it will be a promising tool for economic design of control charts.

关键词： statistical process control control charts Taguchi's loss function optimization particle swarm optimization