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Experimental Study on a Centrifugal Pump with an Open Impeller during Startup Period

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Journal of Thermal Science 2013年第1期22卷 1-6页

作者： Yuliang Zhang Zuchao Zhu Yingzi Jin Baoling Cui Yi Li Huashu Dou The State Key lab of Fluid Power Transmission and Control Zhejiang University The Province Key lab of Fluid Transmission Technology Zhejiang Sci-Tech University

Transient performance of fluid machinery during transient operating periods, such as startup and stopping, has been drawn more attentions recently due to the growing engineering needs. In this paper, the transient behavior of a prototype centrifugal pump with an open impeller during rapid startup period is studied experimentally. The variations of the rotational speed, flow rate, head, and shaft power during rapid startup period are recorded in ex- periments at different discharge valve openings. In addition, the non-dimensional flow rate and head are also used to analyze the transient behavior. The research result shows that the rise characteristic of the rotational speed is not basically changed by working points, while mainly depends on the startnp characteristics of the driving motor. Compared with the rapid rise of the rotational speed, the flow rate rises slowly in the initial stage of startup. Moreover, the flow rate lags behind the rotational speed to rise to final stable value, and the delay becomes more severe with the increase of the discharge valve opening. The shaft power impact phenomenon generally exists in the process of startup. The non-dimensional analysis shows that the non-dimensional head is very high at the very beginning of startup, and quickly falls to the minimum, then gradually rises to final stable value, while the non-dimensional flow rate always shows the rise tendency during whole startup period. In conclusion, it is found from the non-dimensional results that the quasi-steady analysis is unable to accurately assess the transient flow during startup period.

关键词： centrifugal pump open impeller startup experimental study transient behavior

Pores-Preserving Face Cleaning Based on Improved Empirical Mode Decomposition

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Journal of Computer Science & Technology 2009年第3期24卷 557-567页

作者：刘艳丽徐晓刚郭延文王进段鑫陈曦彭群生 State Key lab of CAD & CG Zhejiang University Department of Mathematics Zhejiang University State Key lab of Novel Software Technology Nanjing University

In this paper, we propose a novel method of cleaning up facial imperfections such as bumps and blemishes that may detract from a pleasing digital portrait. Contrasting with traditional methods which tend to blur facial details, our method fully retains fine scale skin textures （pores etc.） of the subject. Our key idea is to find a quantity, namely normalized local energy, to capture different characteristics of fine scale details and distractions, based on empirical mode decomposition, and then build a quantitative measurement of facial skin appearance which characterizes both imperfections and facial details in a unified framework. Finally, we use the quantitative measurement as a guide to enhance facial skin. We also introduce a few high-level, intuitive parameters for controlling the amount of enhancement. In addition, an adaptive local mean and neighborhood limited empirical mode decomposition algorithm is also developed to improve in two respects the performance of empirical mode decomposition. It can effectively avoid the gray spots effect commonly associated with traditional empirical mode decomposition when dealing with high-nonstationary images.

关键词： image enhancement empirical mode decomposition normalized local energy

Big Learning with Bayesian methods

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National Science Review 2017年第4期4卷 627-651页

作者： Jun Zhu Jianfei Chen Wenbo Hu Bo Zhang TNList lab State Key Lab for Intelligent Technology and Systems CBICR Center Department of Computer Science and Technology Tsinghua University

The explosive growth in data volume and the availability of cheap computing resources have sparked increasing interest in Big learning, an emerging subfield that studies scalable machine learning algorithms,systems and applications with Big Data. Bayesian methods represent one important class of statistical methods for machine learning, with substantial recent developments on adaptive, flexible and scalable Bayesian learning. This article provides a survey of the recent advances in Big learning with Bayesian methods, termed Big Bayesian Learning, including non-parametric Bayesian methods for adaptively inferring model complexity, regularized Bayesian inference for improving the flexibility via posterior regularization, and scalable algorithms and systems based on stochastic subsampling and distributed computing for dealing with large-scale applications. We also provide various new perspectives on the large-scale Bayesian modeling and inference.

关键词： Big Bayesian Learning Bayesian non-parametrics regularized Bayesian inference scalable algorithms

Approximating the CIECAM02 color appearance model by means of neural networks

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Chinese Optics Letters 2004年第11期2卷 637-639页

作者：柴冰华廖宁放赵达尊 National lab of Color Science and Engineering

An artificial neural network used to realize the approximating problem of the color appearance model (CAM) CIECAM02 in color management is demonstrated. GretagMacbeth ColorChecker Charts, which now axe widely used in calibration of digital camera, are chosen as samples to implement the forward and reverse color appearance models. When the predictive results are evaluated, for forward model, the output color appearance space is converted to the uniform color space based on CAM and is evaluated, while for reverse model, because the prediction precision is insufficient, we try to convert the color appearance space, which is the cylinder space, to the cube space similar to the red, green, and blue (RGB) space, and the results show that the precision is obviously improved.

关键词： Color computer graphics Colorimetry Mathematical models Neural networks

Self-assembled Nanosheets of Perylene Monoamide Derivative as Sensitive Fluorescent Biosensor for Exonuclease Ⅲ Activity

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Chemical Research in Chinese Universities 2022年第6期38卷 1497-1503页

作者： QIN Yang YANG Yunhan HE Ran ZHOU Laicheng ZHANG Ling PCFM lab and GDHPRC lab School of ChemistrySun Yat-sen UniversityGuangzhou510275P.R.China

Enzymes containing 3′→5′exonuclease activities play an important role in various key cellular and physiological *** development of fluorescence biosensor is an efficient method to detecting enzyme ***,a fluorescence resonance energy transfer(FRET)“on”and“off”strategy for detecting exonuclease III(Exo III)activity has been *** report here that the double-stranded DNA(dsDNA)enables to bind tightly to self-assembled nanosheets of cationic perylene monoimide derivative(PMI-O7)through electrostatic interaction,and the 6-carboxyfluorescein(FAM)-modified dsDNA could be efficiently quenched via FRET between FAM and *** the addition of Exo III,the dsDNA will be digested and the FAM fluorophore will be released,resulting in the fluorescence recovery of *** method provides a simple and sensitive biosensor platform with a low detection limit of 0.077 U/mL for Exo ***,this method exhibits similar and calibration curves for the detection of Exo III in both buffer and fetal bovine serum samples,indicating that this platform has potential to detect Exo III activity in complex samples.

关键词： Nanosheet Fluorescence biosensor Enzymatic reaction

Approximate Poisson disk sampling on mesh

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Science China(Information Sciences) 2013年第9期56卷 194-205页

作者： GENG Bo ZHANG HuiJuan WANG Heng WANG GuoPing Graphics and Interactive Technology lab of Dept. of Computer Science Peking University The Key lab of Machine perception and intelligent MOE

Poisson disk sampling has been widely used in many applications such as remeshing, procedural texturing, object distribution, illumination, etc. While 2D Poisson disk sampling is intensively studied in recent years, direct Poisson disk sampling on 2-manifold surface is rarely covered. In this paper, we present a novel framework which generates approximate Poisson disk distribution directly on mesh, a discrete representation of 2-manifold surfaces. Our framework is easy to implement and provides extra flexibility to specified sampling issues like feature-preserving sampling and adaptive sampling. We integrate the tensor voting method into feature detection and adaptive sample radius calculation. Remeshing as a special downstream application is also addressed. According to our experiment results, our framework is efficient, robust, and widely applicable.

关键词： Poisson disk sampling feature preserving sampling adaptive sampling remeshing tensor voting

HPHT synthesis and electrical transport properties of Sm_xCo_4Sb_(12)

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Journal of Rare Earths 2010年第3期28卷 407-410页

作者：姜一平贾晓鹏于凤荣邓乐郑世钊田永君马红安 National lab of Superhard Materials Jilin University Department of physics Beihua University National lab of Metastable Materials Science and Technology Yanshan University

Samarium-filled skutterudites SmxCo4Sb12(x=0.5,1.0) skutterudite thermoelectric(TE) materials with enhanced power factor were prepared by high-pressure and high-temperature(HPHT) *** microstructure properties were characterized with X-ray diffraction and scanning electron *** electrical resistivities and Seebeck coefficients of those samples were measured in the temperature range of 300-723 K,and the samples of SmxCo4Sb12 showed n-type *** Seebeck coefficient in absolute valu...

关键词： thermoelectric materials electrical transport properties X-ray diffraction high-pressure rare earths

Noninvasive label-Free Detection of Cortisol and Lactate Using Graphene Embedded Screen-Printed Electrode

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Nano-Micro Letters 2018年第3期10卷 42-51页

作者： Satish K.Tuteja Connor Ormsby Suresh Neethirajan BioNano lab School of Engineering University of Guelph

A sensitive and specific immunosensor for the detection of the hormones cortisol and lactate in human or animal biological fluids, such as sweat and saliva, was devised using the label-free electrochemical chronoamperometric technique. By using these fluids instead of blood,the biosensor becomes noninvasive and is less stressful to the end user, who may be a small child or a farm *** graphene oxide(e-RGO) was used as a synergistic platform for signal amplification and template for bioconjugation for the sensing mechanism on a screenprinted electrode. The cortisol and lactate antibodies were bioconjugated to the e-RGO using covalent carbodiimide chemistry. label-free electrochemical chronoamperometric detection was used to analyze the response to the desired biomolecules over the wide detection range. A detection limit of 0.1 ng mL^(-1) for cortisol and 0.1 mM for lactate was established and a correlation between concentration and current was observed. A portable, handheld potentiostat assembled with Bluetooth communication and battery operation enables the developed system for point-of-care applications. A sandwich-like structure containing the sensing mechanisms as a prototype was designed to secure the biosensor to skin and use capillary action to draw sweat or other fluids toward the sensing mechanism. Overall, the immunosensor shows remarkable specificity, sensitivity as well as the noninvasive and point-of-care capabilities and allows the biosensor to be used as a versatile sensing platform in both developed and developing countries.

关键词： Graphene Immunosensor Electrochemical Screen-printed electrodes Cortisol sensor

Transgenic restorer rice line T1c-19 with stacked cry1C*/bar genes has low weediness potential without selection pressure

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Journal of Integrative Agriculture 2016年第5期15卷 1046-1058页

作者： HUANG Yao LI Ji-kun QIANG Sheng DAI Wei-min SONG Xiao-ling Weed Research lab Nanjing Agricultural University

Stacked（insect and herbicide resistant） transgenic rice T1c-19 with cry1C＊/bar genes, its receptor rice Minghui 63（herein MH63） and a local two-line hybrid indica rice Fengliangyou Xiang 1（used as a control） were compared for agronomic performance under field conditions without the relevant selection pressures. Agronomic traits（plant height, tiller number, and aboveground dry biomass）, reproductive ability（pollen viability, panicle length, and filled grain number of main panicles, seed set, and grain yield）, and weediness characteristics（seed shattering, seed overwintering ability, and volunteer seedling recruitment） were used to assess the potential weediness without selection pressure of stacked transgene rice T1c-19. In wet direct-seeded and transplanted rice fields, T1c-19 and its receptor MH63 performed similarly regarding vegetative growth and reproductive ability, but both of them were significantly inferior to the control. T1c-19 did not display weed characteristics; it had weak overwintering ability, low seed shattering and failed to establish volunteers. Exogenous insect and herbicide resistance genes did not confer competitive advantage to transgenic rice T1c-19 grown in the field without the relevant selection pressures.

关键词： stacked transgenic rice T1c-19 agronomic traits reproductive ability weediness