7 results on '"Yao, Qiang"'
Search Results
2. Hausdorff dimension of frequency sets of univoque sequences.
- Author
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Yao-Qiang Li
- Subjects
- *
FRACTAL dimensions , *DYNAMICAL systems , *INTEGERS - Abstract
We study the set Γ consisting of univoque sequences, the set ʌ consisting of sequences in which the lengths of consecutive zeros and consecutive ones are bounded, and their frequency subsets Γa, Γa, Γa and ʌa, ʌa, ʌa consisting of sequences respectively in Γ and ʌ with frequency, lower frequency and upper frequency of zeros equal to some a ∊ [0, 1]. The Hausdorff dimension of all these sets are obtained by studying the dynamical system (ʌ(m), s) where s is the shiftmapandʌ(m) = Γ w ∊ {0, 1}N: w does not contain 0mor1m } for integer m = 3, studying the Bernoulli-type measures on ʌ(m) and finding out the unique equivalent s-invariant ergodic probability measure. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
3. Premixed Flame Response to a Counterflowing Non-thermal Plasma Jet.
- Author
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Tang, Yong, Yao, Qiang, Cui, Wei, Zhuo, Jiankun, and Li, Shuiqing
- Subjects
PLASMA jets ,NON-thermal plasmas ,HEAT release rates ,ENTHALPY ,FLAME ,FIREFIGHTING - Abstract
The response of the laminar premixed flame to a counterflowing non-thermal plasma jet has been studied experimentally and numerically. The plasma is driven by alternating current and sustained in a co-axial dielectric-barrier-discharge (DBD) generator. Particle tracking methods and optical diagnostics of flame emission provide spatio-temporal resolutions of the flow field and subsequent flame response. The deflection of the streamline and flame sheet due to hydrodynamic disturbances results in oscillation of the total heat release rate. Numerical analysis is performed by specifying the flow fluctuation using inflow boundary conditions, as well as solving the flow field and flame structure in the small cylindrical domain sandwiched between the opposed nozzle outlets. The contour plots of temperature and velocity vectors in the simulation solution verify that the flow fluctuation causes deflection, displacement, creases and localized quenching of the flame front. [ABSTRACT FROM AUTHOR]
- Published
- 2020
- Full Text
- View/download PDF
4. Thermal-ignition analysis in wall-bounded boundary-layer flows with an unheated starting length.
- Author
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Li, Shangpeng, Yao, Qiang, and Law, Chung K.
- Subjects
IGNITION temperature ,BOUNDARY layer control ,HOT surface igniters ,FLOW velocity ,NUMERICAL analysis - Abstract
The thermal ignition of a reacting boundary-layer flow over the hot surface of a wedge/cone with an unheated starting length,
, is studied analytically and numerically. For the realistic situation of large activation energy reactions, a locally similar solution is derived and is found to agree well with the numerical solution within a wide range of , geometric angle and the Prandtl number, . An increase in is shown to reduce the minimum ignition distance, because the flow velocity is reduced by the viscous drag over the starting length so that the flow over the heated section is heated to a greater extent for the same distance. [ABSTRACT FROM AUTHOR] - Published
- 2018
- Full Text
- View/download PDF
5. Population-based birth weight reference percentiles for Chinese twins.
- Author
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Dai, Li, Deng, Changfei, Li, Yanhua, Yi, Ling, Li, Xiaohong, Mu, Yi, Li, Qi, Yao, Qiang, and Wang, Yanping
- Abstract
Background:Birth weight percentiles by gestational age are important for assessing prenatal growth and predicting postnatal outcomes of newborns. Several countries have developed nation-specific birth weight references for twins, but China still lacks such references. Methods and results:Birth weight data for twins born between October 2006 and September 2015 were abstracted from the China National Population-based Birth Defects Surveillance System. A total of 54,786 live twin births aged ≥28 weeks of gestation without birth defects were included in the analysis. The LMS method was adopted to generate gestational age-specific birth weight percentiles and curves for male and female twins separately. Significant differences were observed between the current reference and other references developed for Chinese or non-Chinese twins. The neonatal mortality rate in this cohort was 12.3‰, and much higher rates at very early gestation weeks were identified in small-for-gestational-age twins grouped by the newly developed reference cutoffs. Conclusions:The established birth weight centiles represent the first birth weight norm for contemporary Chinese twins and can be a useful tool to assess growth of twins in clinical and research settings.Key MessagesThere have been no population-based birth weight percentiles for Chinese twins prior to this study. The established birth weight centiles for female and male twins are markedly lower than those for Chinese singletons. Twin-specific curves should be used for determining inappropriate for gestational age in twins rather than using existing singleton reference.The birth weight percentiles for twins differed significantly from those for non-Chinese twins. In addition to ethnic influences, the observed differences could be ascribed to variations in prenatal care, fetal or maternal nutrition status or other environmental factors.Neonatal mortality rates varied considerably among twins grouped by the newly developed reference percentiles. Small-for-gestational-age twins had much higher mortality than did appropriate-for-gestational-age twins, highlighting the need to reduce postnatal mortality by improving perinatal health care for twins. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
6. Mechanism and modelling of aluminium nanoparticle oxidation coupled with crystallisation of amorphous Al 2 O 3 shell.
- Author
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Kong, Chengdong, Yu, Dan, Li, Shuiqing, and Yao, Qiang
- Subjects
ALUMINUM oxide ,NANOPARTICLES ,COUPLING reactions (Chemistry) ,CRYSTALLIZATION ,AMORPHOUS substances ,THERMOGRAVIMETRY ,DIFFERENTIAL scanning calorimetry ,TRANSMISSION electron microscopes - Abstract
The oxidation of aluminium nanoparticles coupled with crystallisation of amorphous alumina shell is investigated through the thermogravimetric analyser and differential scanning calorimetry (TGA-DSC) and the transmission electron microscope (TEM). The thermogravimetric (TG) curves show stepwise shapes with temperature increase and could be divided into four stages. The reaction at the second stage is complex, including the simultaneous crystallisation of amorphous alumina (am-Al2O3) and Al oxidation. The crystallisation of am-Al2O3promotes the reaction through generating fast diffusion channels, like micro-cracks and grain boundaries in the oxide shell to accelerate the ionic diffusion. An enhancement factor (freact), which follows a power-law formula with the crystallisation rate, is introduced to quantify the impact of crystallisation on reaction. With heating rate increase, the second stage of TG curves shifts to the high temperature regime and the total weight gain at the second stage decreases slowly. A crystallisation-reaction model is constructed to fit and predict the weight gain after derivation of diffusivities and crystallisation kinetics. Modelling indicates that with heating rate rise, the mass increment at the second stage of TG curves decreases owing to the reduced reaction time, although the reaction is accelerated. The shift of TG curve to higher temperature is due to the polymorphic phase transition. Actually the derived kinetics of the crystallisation of amorphous alumina indicates that the polymorphic phase transformation mechanism works mainly below the heating rate of 3 K s–1. At higher heating rate, the melting of Al takes place firstly and the crystallisation of am-Al2O3follows to enhance the ionic diffusion. Therefore, when the heating rate is fast during ignition or combustion, the Al nanoparticles undergo both the melting of Al and the polymorphic phase transition of am-Al2O3to accelerate the reaction. [ABSTRACT FROM PUBLISHER]
- Published
- 2016
- Full Text
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7. Emerging medical informatics research trends detection based on MeSH terms.
- Author
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Lyu, Peng-Hui, Yao, Qiang, Mao, Jin, and Zhang, Shi-Jing
- Subjects
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MEDICAL informatics , *DIAGNOSTIC imaging , *MEDICAL quality control , *MEDICAL decision making , *COGNITIVE ability - Abstract
The aim of this study is to analyze the research trends of medical informatics over the last 12 years. A new method based on MeSH terms was proposed to identify emerging topics and trends of medical informatics research. Informetric methods and visualization technologies were applied to investigate research trends of medical informatics. The metric of perspective factor (PF) embedding MeSH terms was appropriately employed to assess the perspective quality for journals. The emerging MeSH terms have changed dramatically over the last 12 years, identifying two stages of medical informatics: the 'medical imaging stage' and the 'medical informatics stage'. The focus of medical informatics has shifted from acquisition and storage of healthcare data by integrating computational, informational, cognitive and organizational sciences to semantic analysis for problem solving and clinical decision-making. About 30 core journals were determined by Bradford's Law in the last 3 years in this area. These journals, with high PF values, have relative high perspective quality and lead the trend of medical informatics. [ABSTRACT FROM AUTHOR]
- Published
- 2015
- Full Text
- View/download PDF
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