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Chinese Journal of Chemical Engineering 2018年第12期26卷 2420-2430页

作者： cong qi Maoni Liu Guiqing Wang Yuhang Pan Lin Liang School of Electrical and Power Engineering China University of Mining and Technology

Stable TiO_2–water nanofluids are prepared by a two-step method, stabilities of nanofluids are investigated by precipitation method and transmittance method respectively, and thermal conductivities and viscosities are also measured. An experimental system for studying the heat transfer enhancement of nanofluids is established,and heat transfer and flow characteristics of TiO_2–water nanofluids in heat exchanger systems with a triangular tube and circular tube are experimentally studied. The effects of nanoparticle mass fractions(ω = 0.1 wt%–0.5 wt%) and Reynolds numbers(Re = 800–10000) on the heat transfer and flow performances of nanofluids are analyzed. Fitting formulas for Nusselt number and resistance coefficient of nanofluids in a triangular tube are put forward based on the experimental data. The comprehensive performances of nanofluids in a triangular tube are investigated. It is found that nanofluids in a triangular tube can significantly improve the heat transfer performance at the cost of a small increase in resistance coefficient compared with that in a circular tube, especially the resistance coefficients are almost the same between different nanoparticle mass fractions at turbulent flow. It is also found that the comprehensive evaluation index η decreases with Reynolds number at laminar flow but a critical maximum value appears at turbulent flow.

关键词： Heat transfer Nanoparticles Turbulent flow Triangular tube Comprehensive evaluation index

Experimental study on thermo-hydraulic performances of nanofluids flowing through a corrugated tube filled with copper foam in heat exchange systems

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Chinese Journal of Chemical Engineering 2018年第12期26卷 2431-2440页

作者： Yongliang Wan Runhan Wu cong qi Gang Duan Ruizhao Yang Automotive Engineering Research Institute Shaanxi Heavy Automobile Co.LtdXfan 710200China School of Electrical and Power Engineering China University of Mining and Technology Xuzhou 221116China

Thermo-hydraulic characteristics of TiO_2-water nanofluids in thin-wall stainless steel test tubes(corrugated tube and circular tube) filled with copper foam(40 PPI) are experimentally investigated and compared with those in test tubes without copper foam. The effects of nanoparticle mass concentration on flow and heat transfer performances are investigated. In addition, the mutual restriction relationships between Reynolds number(Re), Nusselt number(Nu) and resistance coefficient(f) are discussed respectively. Also, the comprehensive coefficient of performance(CCP) between heat transfer and pressure drop is evaluated. The results show that core-enhancement region for heat transfer using experimental tubes filled with copper foam is notably different from that of tubes without copper foam. There is a corresponding Reynolds number(about Re = 2400) for the maximum CCP of each condition. And the heat transfer can be enhanced dramatically and sustained at 8000 ≤ Re ≤ 12000.

关键词： Nanofluids Heat transfer enhancement Nanoparticle Corrugated tube

Sound image externalization for headphone based real-time 3D audio

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Frontiers of Computer Science 2017年第3期11卷 419-428页

作者： Yougen YUAN Lei XIE Zhong-Hua FU Ming XU qi cong School of Computer Science Northwestern Polytechnical University Xi'an 710129 China Chinese Aeronautical Radio Electronics Research Institute Shanghai 200233 China

3D audio effects can provide immersive auditory experience, but we often face the so-called in-head localization （IHL） problem in headphone sound reproduction. To ad- dress this problem, we propose an effective sound image externalization approach. Specifically, we consider several important factors related to sound propagation, which include image-source model based early reflections with distance decay, wall absorption and air absorption, late reverberation and other dynamic factors like head movement. We apply our sound image externalization approach to a headphone based real-time 3D audio system. Subjective listening tests show that the sound image externalization performance is significantly improved and the sound source direction is preserved as well. A/B preference test further shows that, as compared with a recent popular approach, the proposed approach is mostly preferred by the listeners.

关键词： 3D audio in-head localization (IHL) headphone reproduction sound image externalization reflections

RT-qPCR normalization of reference genes in different lifehistory stages of Gracilaria vermiculophylla(Rhodophyta)

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Journal of Oceanology and Limnology 2023年第5期41卷 1910-1917页

作者： Yingyue ZHANG Jinxin YANG Ze YANG cong qi Di XU Key Laboratory of Marine Genetics and Breeding Ministry of EducationCollege of Marine Life SciencesOcean University of ChinaQingdao 266003China

The quantitative realtime polymerase chain reaction(RT-qPCR)is a powerful and sensitive method to measure expression of targeted gene but it highly relies on the use of suitable reference genes for data *** evaluated the expressions of 8 housekeeping genes:18S ribosomal rDNA(18S rDNA),28S ribosomal r DNA(28S rDNA),rubisco large subunit(rbc-L),β-actin(ACT),glyceraldehyde-3-phosphate dehydrogenase(GAPDH),elongation factor 1(EF1),β-tubulin(Tub B),and P-phycoerythrin B(PEB),to select the suitable reference genes for different life-history stages(tetrasporophyte,carposporophyte,and male/female gametophyte)of Gracilaria vermiculophylla by absolute quantitative *** geNorm and BestKeeper were used to verify the results acquired from copy number *** show that the expression of identified reference genes varied in comparing groups composed of different type of life *** is suggested that 18S rDNA and TubB could be used for highly complex samples composed of mixed ploidy and phases.18S rDNA and 28S rDNA were also preferred for using among the matured isomorphic *** for samples with different maturities,TubB and ACT were recommended for tetrasporophytes and gametophytes respectively.

关键词： reference gene Gracilaria vermiculophylla life-history stage quantitative real-time polymerase chain reaction(RT-qPCR) red algae

Application of Superhydrophobic Surface on Boiling Heat Transfer Characteristics of Nanofluids

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Energy Engineering 2021年第4期118卷 825-852页

作者： cong qi Yuxing Wang Zi Ding Jianglin Tu Mengxin Zhu School of Electrical and Power Engineering China University of Mining and TechnologyXuzhou221116China

Boiling heat transfer is a mode using the phase change of working medium to strengthen the heat exchange due to its good heat exchange capability,and it is widely used in heat exchange *** have been used in the direction of enhanced heat transfer for their superior thermophysical *** wetting,spreading and ripple phenomena of superhydrophobic surfaces widely exist in nature and daily *** has great application value for engineering *** this article,the boiling heat exchange characteristics of nanofluids on superhydrophobic surface are numerically *** was found that with the increase of superheating degree,the steam volume ratio of unmodified heated surface increases to saturation,while the steam volume and evaporation ratio of modified superhydrophobic surface increase firstly and then *** the same time,bubbles are generated and accumulated more fully on superhydrophobic *** was also found that nanofluids with low viscosity are more affected by superhydrophobic surface characteristics,and the increase is more significant with high superheating degree,and the superhydrophobic surface is beneficial to enhancing boiling heat *** with the simulation results,it could be concluded that the boiling heat exchange performance of CuO-water nano-fluids on the modified superhydrophobic surface is better than that of CuO-ethylene glycol nanofluids under high superheating degree.

关键词： Nanofluids superhydrophobic surface pool boiling heat transfer numerical simulation

A Review of Methods Based on Nanofluids and Biomimetic Structures for the Optimization of Heat Transfer in Electronic Devices

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Fluid Dynamics & Materials Processing 2022年第5期18卷 1205-1227页

作者： Lanqi Chen Yuwei Wang cong qi Zhibo Tang Zhen Tian School of Low-Carbon Energy and Power Engineering China University of Mining and TechnologyXuzhou221116China

Nowadays,the utilization rate of electronic products is increasing while showing no obvious sign of reaching a *** solve the associated“internal heat generation problem”,scientists have proposed two methods or *** first approach consists of replacing the heat exchange medium with a ***,the high surface energy of the nanoparticles makes them prone to accumulate along the heat transfer *** second method follows a different *** tries to modify the surface structure of the electronic components in order to reduce the fluid-dynamic drag and improve the rate of heat *** article reviews these effects considering different types of nanofluid and different shapes,sizes,and arrangements of“biomimetic grooves”.The idea to use these two methods in a combined fashion(to improve heat transfer and reduce flow resistance at the same time)is also developed and discussed critically to a certain extent.

关键词： Nanofluids biomimetic structure drag reduction characteristic thermal management

Fracture sealing performance of granular lost circulation materials at elevated temperature:A theoretical and coupled CFD-DEM simulation study

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Petroleum Science 2024年第1期21卷 567-581页

作者： Chong Lin qi-cong Xu Lie-Xiang Han Gao Li Hai He Hong-Ling Zhou Ji-Ping She CCDC Drilling&Production Technology Research Institute Guanghan618300SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Southwest Petroleum UniversityChengdu610500SichuanChina College of Materials Science and Engineering Chongqing UniversityChongqing400044China State Key Lab of Oil and Gas Reservoir Geology and Exploitation(Chengdu University of Technology) Chengdu610059SichuanChina College of Energy Chengdu University of TechnologyChengdu610059SichuanChina

Lost circulation is a common downhole problem of drilling in geothermal and high-temperature,high-pressure(HTHP)*** circulation material(LCM)is a regular preventive and remedial measure for lost ***,conventional LCMs seem ineffective in high-temperature *** may be due to the changes in the mechanical properties of LCMs and their sealing performance under high-temperature *** understand how high temperature affects the fracture sealing performance of LCMs,we developed a coupled computational fluid dynamics-discrete element method(CFD-DEM)model to simulate the behavior of granular LCMs in *** summarized the literature on the effects of high temperature on the mechanical properties of LCMs and the rheological properties of drilling *** conducted sensitivity analyses to investigate how changing LCM slurry properties affected the fracture sealing efficiency at increasing *** results show that high temperature reduces the size,strength,and friction coefficient of LCMs as well as the drilling fluid ***,softer,and less frictional LCM particles have lower bridging probability and slower bridging *** particles tend to form dual-particle bridges rather than single-particle *** result in a deeper,tighter,but unstable sealing *** drilling fluid viscosity leads to faster and shallower sealing zones.

关键词： Geothermal well drilling HTHP formationLost circulation material CFD-DEM Fracture sealing

Effects of angiotensin receptor blockers and angiotensin-converting enzyme inhibitors on COVID-19

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World Journal of Clinical Cases 2021年第20期9卷 5462-5469页

作者： Xiao-Long Li Tao Li qi-cong Du Li Yang Kun-Lun He Department of Diagnostic Radiology PLA General HospitalBeijing 100853China Department of Radiology The First Medical Center of PLA General HospitalBeijing 100853China Department of Diagnostic Radiology The First Medical Center of PLA General HospitalBeijing 100853China Translational Medical Research Center Key Laboratory of Ministry of Industry and Information Technology of Biomedical Engineering and Translational MedicineMedical Innovation Research Division of Chinese PLA General HospitalBeijing 100853China

BACKGROUND The World Health Organization reported that 28637952 people worldwide had been infected with severe acute respiratory syndrome coronavirus 2,the causative agent of coronavirus disease 2019(COVID-19),by September *** The aim was to investigate whether long-term use of renin-angiotensin-aldosterone system(RAAS)inhibitors for the treatment of hypertension aggravates the performance of COVID-19 patients with *** This was a retrospective analysis of lung computed tomography(CT)data and laboratory values of COVID-19 patients with hypertension who were admitted to Huoshenshan Hospital,Wuhan,Hubei Province,between February 18 and March 31,*** were divided into two *** A included 19 people who were long-term users of RAAS inhibitors for hypertension;and group B included 28 people who were randomly selected from the database and matched with group A by age,sex,basic diseases,and long-term use of other antihypertensive *** patients underwent a series of CT and laboratory *** compared the most severe CT images of the two groups and the laboratory examination results within 2 d of the corresponding CT *** The time until the most severe CT images from the onset of COVID-19 was 30.37±14.25 d group A and 26.50±11.97 d in group *** difference between the two groups was not significant(t=1.01,P=0.32).There were no significant differences in blood laboratory values,C-reactive protein,markers of cardiac injury,liver function,or kidney function between the two *** was no significant difference in the appearance of the CT images between the two *** semiquantitative scores of each involved lobe were 11.84±5.88 in group A and 10.36±6.04 group *** difference was not significantly different(t=0.84,P=0.41).CONCLUSION Chest CT is an important imaging tool to monitor the characteristics of COVID-19 and the degree of lung *** use of RAAS inhibitors is not related to the severity of COVID-19,and

关键词： COVID-19 infection Hypertensive patients Angiotensin-converting enzyme inhibitors Angiotensin receptor blockers

CFD-Based Optimization of Hot Primary-Air Pipe Networks in Power Plant Milling Systems

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Fluid Dynamics & Materials Processing 2020年第3期16卷 623-636页

作者： qingyun Yan You Li Yuanhong Zhu Kui Cheng Xueli Huang cong qi Xuemin Ye Jiangxi Vocational and Technical College of Electricity Nanchang330032China North China Electric Power University Baoding071003China Power China Jiangxi Electric Power Engineering Co. Ltd.Nanchang330096China

A hot primary-air pipe system is the bridge connecting an air-preheater with a coal mill in power generation *** effective geometrical configuration of the pipe network greatly affects the air flow distribution and consequently influences the safe and economic operation of milling systems in power *** order to improve the properties of the air flow,in the present work the SIMPLEC method is used to simulate numerically the flow field for the original layout of the *** a result,the internal mechanisms influencing the uneven pressure drop in each branch are explored and three optimization schemes are proposed *** numerical results indicate that,for the original layout,the local pressure drop of the tee section accounts for approximately 74%of the total drop of the system,with other pressure drops depending on the specific branch *** is shown that after optimization,a roughly balanced flow resistance and flow rate can be *** with the original layout,the pressure drop relating to different branches is significantly reduced.

关键词： Hot primary-air pipe flow dynamics layout optimization numerical simulation

Spectroscopic Properties of Perturbed Ba 6p3/2ns Autoionizing States

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Chinese Physics Letters 1999年第8期16卷 560-562页

作者： LÜ Jun DAI Chang-jian LI cong-qi LIU Zheng-dong TANG Jing-chang Department of Physics Zhejiang UniversityHangzhou 310027 CCAST(World Laboratory) P.O.Box 8730Beijing 100080

The excitation spectra of the Ba 6p_(3/2)ns(J=1)autoionizing states with n ranging from 8 to 12 are measured using multistep laser excitation *** measurements manifest that these states are strongly perturbed by the degenerate 6p_(1/2)nl states,as the resonance profiles are structured according to the corresponding perturbing *** experimental data are well reproduced by multichannel-quantum-defect theory,with the parameters obtained from a previous R-matrix calculation.

关键词： calculation. states. excitation