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9篇 您的检索式:作者名="Mengkai Li"
    题名 作者 年代 出处 被引量
1Collision Avoidance Strategy Supported by LTE-V-Based Vehicle Automation and Communication Systems for Car Following显示文摘We analyzed and improved a collision avoidance strategy, which was supported by Long Term EvolutionVehicle(LTE-V)-based Vehicle-to-Vehicle(V2 V) communication, for automated vehicles. This work was completed in two steps. In the first step, we analyzed the probability distribution of message transmission time, which was conditional on transmission distance and vehicle density. Our analysis revealed that transmission time exhibited a near-linear increase with distance and density. We also quantified the trade-off between high/low resource reselection probabilities to improve the setting of media access parameters. In the second step, we studied the required safety distance in accordance with the response time, i.e., the transmission time, derived on the basis of a novel concept of Responsibility-Sensitive Safety(RSS). We improved the strategy by considering the uncertainty of response time and its dependence on vehicle distance and density. We performed theoretical analysis and numerical testing to illustrate the effectiveness of the improved robust RSS strategy. Our results enhance the practicability of building driverless highways with special lanes reserved for the exclusive use of LTE-V vehicles.Jiayang Li Yi Zhang Mengkai Shi Qi Liu Yi Chen 2020Tsinghua Science and Technology2020,25,1:5
2Nonlinear Optical Properties of Perfectly Polarized KIO_(3) Single Crystal显示文摘The nonlinear optical properties of a perfectly polarized KIO^single crystal were investigated.The principal refractive indices and nonlinear optical coefficients have been measured.The results are as follows:n1=1.6967,n2=1-8329,n3=1.8358 for 0.5893μm;d_(31)=1.2|d_(31)(LiIO_(3))|,d_(32)=1.8|d_(31)(LiIO_(3))|.The in tensity of the frequency-doubled light of the KIO_(3 )single crystal with 2.96 mm thickness is 1.2 times as large as that of the KTP single crystal with the same thickness.YIN Xin LU Mengkai ZHANG Shaojun LI Fuqi 1992Chinese Physics Letters1992,9,2:2
3Degradation of micropolluants in flow-through VUV/UV/H2O2 reactors: Effects of H2O2 dosage and reactor internal diameter显示文摘The degradation of atrazine (ATZ),sulfamethoxazole (SMX) and metoprolol (MET) in flowthrough VUV/UV/H2O2reactors was investigated with a focus on the effects of H2O2dosage and reactor internal diameter (ID).Results showed that the micropollutants were degraded efficiently in the flow-through VUV/UV/H2O2reactors following the pseudo first-order kinetics (R2>0.92).However,the steady-state assumption (SSA) kinetic model being vital in batch reactors was found invalid in flow-through reactors where fluid mixing was less sufficient.With the increase of H2O2dosage,the ATZ removal efficiency remained almost constant while the SMX and MET removal was enhanced to different extents,which could be explained by the different reactivities of the pollutants towards HO·.A larger reactor ID resulted in lower degradation rate constants for all the three pollutants on account of the lower average fluence rate,but the change in energy efficiency was much more complicated.In reality,the electrical energy per order (EEO) of the investigated VUV/UV/H2O2treatments ranged between 0.14–0.20,0.07–0.14 and 0.09–0.26 k Wh/m3/order for ATZ,SMX and MET,respectively,with the lowest EEOfor each pollutant obtained under varied H2O2dosages and reactor IDs.This study has demonstrated the efficiency of VUV/UV/H2O2process for micropollutant removal and the inadequacy of the SSA model in flow-through reactors,and elaborated the influential mechanisms of H2O2dosage and reactor ID on the reactor performances.Lumeng Zhan Wentao Li Li Liu Tao Han Mengkai Li Zhimin Qiang 2021Journal of Environmental Sciences2021,33,12:2
4The Stagnant Export Upgrading in Northeast China:Evidence from Value-added Tax Reform显示文摘China's 2004 value-added tax(VAT)pilot reform in the Northeast region,which changed the VAT from production type to consumption type,introduced a sizable tax credit for fixed investment in manufacturing industries,leading to more investment and higher productivity at firm level.This paper,however,uses difference-in-difference estimation and finds a negative structural effect;that is,the VAT pilot reform leads to a reduction in the export sophistication of Northeast cities relative to other cities in China,and the results hold for a battery of robustness checks.It is found that resources are reallocated towards less-sophisticated industries.As the products with higher export sophistication are more skill and research and development(R&D)intensive,the shortfalls of skilled labor and R&D spending hinder the upgrading process.With a new round of revitalization plans in the Northeast,policymakers should be cautious with similar structural effects and focus on increasing skilled labor supply and R&D investment.Yan Du Mengkai Yang Jing Li Yunong Li 2020China & World Economy2020,28,4:1
5Growth,Spectra and Influence of Annealing Effect on Laser Properties of Nd:YVO4 Crystal显示文摘Zhang Huaijin Meng Xianlin Zhu Li Wang Changqing Chow Y T Lu Mengkai 2000Optical Materials2000,14,:1
6Improving photoelectrochemical activity of dye sensitized solar cell by a bilayered electrode with an overlayer of mesoporous anatase TiO_2显示文摘For better performance of dye sensitized solar cells(DSSCs) ,a bilayer structured electrode was constructed by employing a mesoporous anatase TiO2 overlayer above a commercial P25 TiO2 nanoparticles underlayer. The mesoporous anatase TiO2,prepared through a facile surfactant-assisted sol-gel process,possessed large pore size and well inter-connected network structure,both beneficial for dye adsorption and electron transfer. The dye adsorption capability of the mesoporous TiO2 was nearly twice that of the P25 counterpart. In the electrode,the mesoporous TiO2 film enhanced both dye adsorption and lightharvest,to increase photocurrent(Jsc) from 12.32 to 14.78 mA/cm2. Compared to the single P25 TiO2 film,the synergy of the mesoporous TiO2 and the P25 TiO2 nanoparticle films in the electrode resulted in a 24% improvement in light-to-electricity conversion efficiency(η) . This bilayered electrode provides an alternative approach for further developing a photovoltaic device with better cell performance.Jun Jiang Jian Zhang Feng Gu Wei Shao Chunzhong Li Mengkai Lu 2011Particuology2011,9,3:1
7Revealing photon transmission in an ultraviolet reactor: Advanced approaches for measuring fluence rate distribution in water for model validation显示文摘Fluence rate(FR) distribution(optical field) is of great significance in the optimal design of ultraviolet(UV) reactors for disinfection or oxidation processes in water treatment. Since the1970 s, various simulation models have been developed, which can be combined with computational fluidic dynamic software to calculate the fluence delivered in a UV reactor. These models strive for experimental validation and further improvement, which is a major challenge for UV technology in water treatment. Herein, a review of the simulation models of the FR distribution in a UV reactor and the applications of the current main experimental measurement approaches including conventional flat-type UV detector, spherical actinometer,and micro-fluorescent silica detector(MFSD), is presented. Moreover, FR distributions in a UV reactor are compared between various simulation models and MFSD measurements.In addition, the main influential factors on the FR distribution, including inner-wall reflection, refraction and shadowing effects of adjacent lamps, and turbidity effect are discussed,which is helpful for improving the accuracy of the simulation models and avoiding dark regions in the reactor design. This paper provides an overview on the simulation models and measurement approaches for the FR distribution, which is helpful for the model selection in fluence calculations and gives high confidence on the optimal design of UV reactors in regard to present methods.Mengkai Li Fei Lou Zhe Sun Wentao Li James R.Bolton Zhimin Qiang 2021Journal of Environmental Sciences2021,33,12:1
8CAV driving safety monitoring and warning via V2X-based edge computing system显示文摘Driving safety and accident prevention are attracting increasing global interest.Current safety monitoring systems often face challenges such as limited spatiotemporal coverage and accuracy,leading to delays in alerting drivers about potential hazards.This study explores the use of edge computing for monitoring vehicle motion and issuing accident warnings,such as lane departures and vehicle collisions.Unlike traditional systems that depend on data from single vehicles,the cooperative vehicle-infrastructure system collects data directly from connected and automated vehicles(CAVs)via vehicle-to-everything communication.This approach facilitates a comprehensive assessment of each vehicle’s risk.We propose algorithms and specific data structures for evaluating accident risks associated with different CAVs.Furthermore,we examine the prerequisites for data accuracy and transmission delay to enhance the safety of CAV driving.The efficacy of this framework is validated through both simulated and real-world road tests,proving its utility in diverse driving conditions.Cheng CHANG Jiawei ZHANG Kunpeng ZHANG Yichen ZHENG Mengkai SHI Jianming HU Shen LI Li LI 2024Frontiers of Engineering Management2024,11,1:0
9Macrophage LMO7 deficiency facilitates inflammatory injury via metabolic-epigenetic reprogramming显示文摘Inflammatory bowel disease(IBD)is a formidable disease due to its complex pathogenesis.Macrophages,as a major immune cell population in IBD,are crucial for gut homeostasis.However,it is still unveiled how macrophages modulate IBD.Here,we found that LIM domain only 7(LMO7)was downregulated in pro-inflammatory macrophages,and that LMO7 directly degraded 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3(PFKFB3)through K48-mediated ubiquitination in macrophages.As an enzyme that regulates glycolysis,PFKFB3 degradation led to the glycolytic process inhibition in macrophages,which in turn inhibited macrophage activation and ultimately attenuated murine colitis.Moreover,we demonstrated that PFKFB3 was required for histone demethylase Jumonji domaincontaining protein 3(JMJD3)expression,thereby inhibiting the protein level of trimethylation of histone H3 on lysine 27(H3K27me3).Overall,our results indicated the LMO7/PFKFB3/JMJD3 axis is essential for modulating macrophage function and IBD pathogenesis.Targeting LMO7 or macrophage metabolism could potentially be an effective strategy for treating inflammatory diseases.Shixin Duan Xinyi Lou Shiyi Chen Hongchao Jiang Dongxin Chen Rui Yin Mengkai Li Yuseng Gou Wenjuan Zhao Lei Sun Feng Qian 2023Acta Pharmaceutica Sinica B2023,13,12:0
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