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Conduction-convection coupled heat transfer around a hollow cylinder under different buoyancy forces

Chinese Journal of Aeronautics 2024年第4期37卷 216-228页

作者： Wanyu ZHANG Jingyi wu guang YANG Institute of Refrigeration and Cryogenics Shanghai Jiao Tong UniversityShanghai 200240China

In order to clarify the effect of a buoyancy force on conduction–convection coupled heat transfer in a hollow cylinder, the flow and thermal characteristics were analyzed using an RNG k-ε turbulence model. The Reynolds number was fixed at 1.014 × 10^(6), and the Rayleigh number varied from 1.122 × 10^(10)to 1.088 × 10^(11). Results have shown that, when considering the effect of an opposed buoyancy force, increasing the Rayleigh number has a positive impact on the rate of change and uniformity of the cylinder temperature. The temperature distributions along the axial and circumferential directions are similar for different Rayleigh numbers, but extreme values *** the axial direction, the maximum temperature is obtained at the interface between the variable-diameter part and the constant-diameter part. The maximum dimensionless temperature value decreases to 0.12 when the Rayleigh number increases to 1.088 × 10^(11). Along the circumferential direction, the temperature distribution is affected by the buoyancy force, which results in the temperature of the upper part being higher than that of the lower part. After nondimensionalization of the temperature and time, a correlation was proposed to illustrate the transient heat transfer process quantitatively. The standard deviation of the maximum relative temperature, representing the temperature uniformity, was also calculated. It was found that the difference in the direction of the buoyancy force made a huge difference. Compared with the opposed buoyancy force, the maximum dimensionless temperature is almost two times higher with an assisted buoyancy force. Similarly, the heat transfer coefficient with an assisted buoyancy force is half of that with an opposed buoyancy force. Overall, an assisted buoyancy force plays a negative role in terms of thermal characteristics. The flow field around the hollow cylinder was also illustrated to reveal the mechanism of the buoyancy force on magnitude and direction aspects

关键词： Buoyancy Conduction-convection heat transfer Transient analysis Hollow cylinder Non-dimensionalization

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Effects of Nerve Growth Factor Expression on Perineural Invasion and Worse Prognosis in Early-Stage Cervical Cancer

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Chinese Medical Journal 2018年第19期131卷 2360-2363页

作者： Ying Long De-Sheng Yao You-Sheng Wei guang-teng wu Department of Gynecologic Oncology Affiliated Tumor Hospital of Guangxi Medical University Nanning Guangxi 530021 China

To the Editor： Several kinds of malignant tumors show perineural invasion （PNI）, which can cause locoregional recurrence and reduce the likelihood of survival after surgery. Our previous study has shown that PNI in cervical cancer is associated with other pathology risk features, and other studies have shown that it is a predictor of poor prognosis. These findings highlight the importance of clarifying the molecular mechanism of PNI.

关键词： PANCREATIC-CANCER CARCINOMA

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GAMYB transcription factor LoMYB65 from lily plays a vital role in pollen development

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Horticultural Plant Journal 2024年第1期10卷 223-238页

作者： Xinyue Liu Ling He Ze wu Nianjun teng Key Laboratory of Landscaping Agriculture Ministry of Agriculture and Rural AffairsCollege of HorticultureNanjing Agricultural UniversityNanjingJiangsu 210095China Key Laboratory of Biology of Ornamental Plants in East China National Forestry and Grassland AdministrationCollege of HorticultureNanjing Agricultural UniversityNanjingJiangsu 210095China Jiangsu Graduate Workstation of Nanjing Agricultural University and Nanjing Oriole Island Modern Agricultural Development Co. Ltd.NanjingJiangsu 210043China

Lily(Lilium spp.)is an important horticultural crop,but its use is limited due to serious pollen contamination *** are many studies on pollen development in model plants,but few on flower crops such as ***(GA)is a large class of hormones and plays an important role in plant vegetative growth and reproductive *** is a group of the R2R3-MYB family upregulated by gibberellin,and plays an important role in anther ***,we isolated a novel GAMYB,named LoMYB65,from lily,which was closely related to the AtMYB65 and AtMYB33 in *** quantitative PCR results showed that LoMYB65 was mainly expressed in lily ***65 could be activated by 288μmol·L^(-1)GA3treatment and the LoMYB65 protein was located in the nucleus and cytoplasm,and had transactivation in yeast and tobacco leaf *** conserved motif within 226 amino acids of the C-terminal of LoMYB65 contributed to its *** of LoMYB65 caused dwarf phenotype,unnormal tapetum development,less seeds of siliques in transgenic Arabidopsis plants,the transgenic plants showed partly male ***,silencing of LoMYB65 with VIGS(Virus Induced Gene Silencing)in lily anthers caused unnormal pollen development and reduced the pollen *** of LoMYB65 in Arabidopsis and silencing of LoMYB65 in lily resulted in decreased pollen counts,so we speculate that LoMYB65 may be ***,these findings suggest that LoMYB65 may play an important role in anther development and pollen formation in ***65 may provide a useful candidate gene for pollenless breeding of lily.

关键词： Lily Anther development Pollen pollution GAMYB VIGS

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Eutectogel-based self-powered wearable sensor for health monitoring in harsh environments

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Nano Research 2024年第6期17卷 5559-5568页

作者： Junpeng wu Xinru teng Lu Liu Hongzhi Cui Xiaoyi Li College of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Key Lab for Special Functional Materials of Ministry of Education School of Materials Science and EngineeringHenan UniversityKaifeng 475004China

Triboelectric nanogenerators(teng)have emerged as a highly promising energy harvesting technology,attracting significant attention in recent years for their broad ***-based tengs,with superior stretchability and sensitivity,have been widely reported as wearable ***,the traditional hydrogel-based tengs suffer from freezing at low temperatures and drying at high temperatures,resulting in *** this study,we introduce an anti-freezing eutectogel,which uses a deep eutectic solvent(DES),to improve the stability and electrical conductivity of tengs in harsh environmental *** eutectogel-based teng(E-teng)produces an open-circuit voltage of 776 V,a short-circuit current of 1.54μA,and a maximum peak power of 1.1 ***,the E-teng exhibits exceptional mechanical properties with an elongation at a break of 476%under ***,it maintains impressive performances across a wide temperature range from−18 to 60℃,with conductivities of 2.15 S/m at−10℃and 1.75 S/m at−18℃.Based on the excellent weight stability of the E-teng sensor,motion sensing can be achieved in the air,and even ***,the versatility of the E-teng can serve as a wearable sensor,by integrating it with Bluetooth *** self-powered E-teng can monitor various human motion signals in real-time and send the health signals directly to mobile *** research paves a new road for the applications of tengs in harsh environments,offering wireless flexible sensors with real-time health signal monitoring capabilities.

关键词： triboelectric nanogenerators self-powered harsh environment health monitoring Eutectogel

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State estimation for delayed switched positive systems: delayed radius approach

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Science China(Information Sciences) 2024年第8期67卷 190-205页

作者： Weizhong CHEN Zhongyang FEI Xudong ZHAO Zheng-guang wu School of Electronics and Information Xi'an Polytechnic University Research Institute of Intelligent Control and Systems Harbin Institute of Technology Key Laboratory of Intelligent Control and Optimization for Industrial Equipment of Ministry of Education Dalian University of Technology School of Control Science and Engineering Dalian University of Technology State Key Laboratory of Industrial Control Technology Institute of Cyber-Systems and ControlZhejiang University

In this paper, an interval estimation scheme is developed for delayed switched positive systems（DSPS） with mode-dependent average dwell time switching. A lossless zonotopic estimation approach is proposed for the delayed intersection zonotope with the positive generator matrix. First, considering the existence of asynchronism between the system mode and the correction matrix mode, the mismatched intersection zonotope is constructed for DSPS to verify the consistency between the system model and ***, by utilizing the introduced radius definitions, the ?∞performance is addressed to optimize the size of delayed intersection zonotopes. Subsequently, we present a joint-design approach of switching signals and the mode-dependent correction matrix by constructing positive generator matrix-based delayed radius functions. Furthermore, guaranteed nonnegative state bounds are derived for the considered DSPS based on the proposed lossless zonotopic estimation criteria. Finally, detailed simulations are conducted to validate the feasibility and superiority of the developed methods.

关键词： delayed switched positive systems interval estimation asynchronous correction matrix zonotopes mode-dependent average dwell time

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Effects of Diesel Concentration on the Thermal Conductivity,Specific Heat Capacity and Thermal Diffusivity of Diesel-Contaminated Soil

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Journal of Thermal Science 2024年第2期33卷 696-709页

作者： wu Yuhao wu Yuefei LUO Gubai ZHANG teng WANG Qing FAN Liwu SONG Xin YU Zitao Key Laboratory of Clean Energy and Carbon Neutrality of Zhejiang Province Zhejiang UniversityHangzhou310027China State Key Laboratory of Clean Energy Utilization Zhejiang UniversityHangzhou310027China Institute of Thermal Science and Power Systems School of Energy EngineeringZhejiang UniversityHangzhou310027China Center Environmental Protection Technology Company Limited Beijing100176China Institute of Soil Science Chinese Academy of SciencesNanjing210008China

High energy consumption is a serious issue associated with in situ thermal desorption(TD)remediation of sites contaminated by petroleum hydrocarbons(PHs).The knowledge on the thermophysical properties of contaminated soil can help predict accurately the transient temperature distribution in a remediation site,for the purpose of energy ***,such data are rarely reported for PH-contaminated *** this study,by taking diesel as a representative example for PHs,soil samples with constant dry bulk density but different diesel mass concentrations ranging from 0% to 20% were prepared,and the variations of their thermal conductivity,specific heat capacity and thermal diffusivity were measured and analyzed over a wide temperature range between 0℃ and 120℃.It was found that the effect of diesel concentration on the thermal conductivity of soil is negligible when it is below 1%.When diesel concentration is below 10%,the thermal conductivity of soil increases with raising the ***,when diesel concentration becomes above 10%,the change of the thermal conductivity of soil with temperature exhibits the opposite *** is mainly due to the competition between soil minerals and diesel,because the thermal conductivity of minerals increases with temperature,whereas the thermal conductivity of diesel decreases with *** analysis results showed that,compared with temperature,the diesel concentration has more significant effects on soil thermal *** of the diesel concentration,with the increase of temperature,the specific heat capacity of soil increases,while the thermal diffusivity of soil *** addition,the results of a control experiment exhibited that the relative differences of the thermal conductivity of the soil samples containing the same concentration of both diesel and a pure alkane are all below 10%,indicating that the results obtained with diesel in this study can be extended to the family of PHs.A theo

关键词： contaminated soil diesel concentration thermal conductivity specific heat capacity thermal diffusivity thermal desorption fractal model

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Effect of Mn addition on microstructure and mechanical properties of GX40CrNiSi25-12 austenitic heat resistant steel

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China Foundry 2024年第3期21卷 205-212页

作者： Guan-yu Jiang Meng-wu wu Xiao-guang Yang Hui Wang Yu-yuan Zhu Hubei Key Laboratory of Advanced Technology for Automotive Components Wuhan University of TechnologyWuhan 430070China Hubei Longzhong Laboratory Xiangyang 441000HubeiChina Wescast Industries(China)Co. Ltd.Wuhan 430100China

Three types of steels were designed on the basis of GX40CrNiSi25-12 austenitic heat resistant steel by adding different Mn contents(2wt.%,6wt.%,and 12wt.%).Thermodynamic calculation,microstructure characterization and mechanical property tests were conducted to investigate the effect of Mn addition on the microstructure and mechanical properties of the austenitic heat resistant *** show that the matrix structure in all the three types of steels at room temperature is completely *** NbC and M_(23)C_(6)precipitate at grain boundaries of austenite *** the increase of Mn content,the number of carbides increases and their distribution becomes more *** the Mn content increases from 1.99%to 12.06%,the ultimate tensile strength,yield strength and elongation increase by 14.6%,8.0%and 46.3%,*** improvement of the mechanical properties of austenitic steels can be explained by utilizing classic theories of alloy strengthening,including solid solution strengthening,precipitation strengthening,and grain *** increase in alloy strength can be attributed to solid solution strengthening and precipitation strengthening caused by the addition of *** improvement of the plasticity of austenitic steels can be explained from two aspects:grain refinement and homogenization of precipitated phases.

关键词： austenitic heat resistant steel manganese microstructure mechanical properties

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Mixed Integer Robust Programming Model for Multimodal Fresh Agricultural Products Terminal Distribution Network Design

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工程与科学中的计算机建模(英文) 2024年第1期138卷 719-738页

作者： Feng Yang Zhong wu Xiaoyan teng Business School University of Shanghai for Science and TechnologyShanghai200093China School of Management Shanghai University of International Business and EconomicsShanghai201620China

The low efficiency and high cost of fresh agricultural product terminal distribution directly restrict the operation of the entire supply *** reduce costs and optimize the distribution network,we construct a mixed integer programmingmodel that comprehensively considers tominimize fixed,transportation,fresh-keeping,time,carbon emissions,and performance incentive *** analyzed the performance of traditional rider distribution and robot distribution modes in *** addition,the uncertainty of the actual market demand poses a huge threat to the stability of the terminal distribution *** order to resist uncertain interference,we further extend the model to a robust counterpart *** results of the simulation show that the instability of random parameters will lead to an increase in the *** with the traditional rider distribution mode,the robot distribution mode can save 12.7%on logistics costs,and the distribution efficiency is *** research can provide support for the design of planning schemes for transportation enterprise managers.

关键词： Fresh agricultural product terminal distribution network rider delivery robot delivery uncertainty

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A model reduction approach for discrete-time linear time-variant systems with delayed inputs

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Science China(Information Sciences) 2024年第4期67卷 197-217页

作者： Ai-Guo wu guang-Ren DUAN Yu WANG Jie ZHANG School of Mechanical Engineering and Automation Harbin Institute of Technology(Shenzhen) HIT wuhu Robot Technology Research Institute Center for Control Science and Technology Southern University of Science and Technology

A model reduction approach is presented for discrete-time linear time-variant input-delayed systems. According to this proposed approach, a dynamical variable is constructed by taking advantage of the current state and historical information of input. It is revealed that the behavior of this dynamical variable is governed by a discrete-time linear delay-free system. It is worth noting that the presented variable transformation does not require the system matrix to be invertible. Based on the reduced delay-free models,stabilizing control laws can be easily obtained for the original delayed system. For the case with a single input delay, the constructed variable is an exact prediction for the future state, and thus the stabilizing control law could be designed by replacing the future state with its prediction. Finally, three discrete-time periodic systems with delayed input are employed to illustrate how to utilize the presented model reduction approaches.

关键词： reduction approach predictor-based feedback time-varying systems delayed input periodic system

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Electrostatic generator enhancements for powering IoT nodes via efficient energy management

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Microsystems & Nanoengineering 2024年第2期10卷 143-152页

作者： Zibo wu Zeyuan Cao Junchi teng Rong Ding Jiani Xu Xiongying Ye State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua University100084BeijingChina

Electrostatic generators show great potential for powering widely distributed electronic devices in Internet of Things(IoT)***,a critical issue limiting such generators is their high impedance mismatch when coupled to electronics,which results in very low energy utilization ***,we present a high-performance energy management unit(EMU)based on a spark-switch tube and a buck converter with an RF *** optimizing the elements and parameters of the EMU,a maximum direct current output power of 79.2 mW m^(-2)rps^(-1)was reached for a rotary electret generator with the EMU,achieving 1.2 times greater power output than without the ***,the maximum power of the contact-separated triboelectric nanogenerator with an EMU is 1.5 times that without the *** excellent performance is attributed to the various optimizations,including utilizing an ultralow-loss spark-switch tube with a proper breakdown voltage,adding a matched input capacitor to enhance available charge,and incorporating an RF inductor to facilitate the high-speed energy transfer *** on this extremely efficient EMU,a compact self-powered wireless temperature sensor node was demonstrated to acquire and transmit data every 3.5 s under a slight wind speed of 0.5 m/*** work greatly promotes the utilization of electrostatic nanogenerators in practical applications,particularly in IoT nodes.

关键词： IoT power generator

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