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超临界环境下燃料液滴蒸发的分子动力学模拟

工程热物理学报 2017年第12期38卷 2745-2751页

作者：肖国炜罗开红马骁帅石金清华大学汽车安全与节能国家重点实验室北京100084 清华大学燃烧能源中心北京100084 Department of Mechanical Engineering University College LondonLondon WCIETJEUK

本文采用分子动力学模拟的方法,研究了超临界压力下正十二烷液滴在氮气环境中的蒸发过程,环境温度覆盖了从亚临界到超临界的范围。研究表明,高压下的蒸发过程相对低压下的经典理论有明显偏离,其蒸发速率不符合D2定律的预测;环境压力和... 详细信息

本文采用分子动力学模拟的方法,研究了超临界压力下正十二烷液滴在氮气环境中的蒸发过程,环境温度覆盖了从亚临界到超临界的范围。研究表明,高压下的蒸发过程相对低压下的经典理论有明显偏离,其蒸发速率不符合D2定律的预测;环境压力和温度均对蒸发速率有明显影响,并且环境压力的提高还会使氮气溶解度和界面厚度显著增大。此外,分析还证明超临界环境下气液界面可能会变为连续相,从而使蒸发过程变成扩散主导的混合过程。

关键词：正十二烷液滴蒸发超临界分子动力学

Rapid Access to Oxabicyclo[2.2.2 ]octane Skeleton through Cu(I)- Catalyzed Generation and Trapping of Vinyl-o-quinodimethanes (Vinyl-0-QDMs)

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Chinese Journal of Chemistry 2020年第10期38卷 1052-1056页

作者： Hejiang luo Chuan He Huanfeng Jiang shifa Zhu Key Laboratory of Functional Moleculor Engineering of Guangdong Province School of Chemistry and Chemical EngineeringSouth China University of TechnologyGuangzhouGuangzhou 510640China

Summary of main observation and conclusion A Cu(I)-catalyzed three-component reaction of terminal enynals/enynones,diazo compounds,and al kenes has been *** this method,a series of oxabicyclo[2.2.2]octanes were effectively synthesized in high yields under mild reaction *** transformation is proposed to proceed through trapping of the cyclic vinyl-o-quinodimethanes(vinyI-o-QDMs)species,which were generated from terminal enynals/enynones and diazo compounds by *** obvious advantages of wide substrate scopes,mild reaction conditions,and high seteroselectivity and atom eficiency make this reaction highly appealing for construction of highly rigid[2.2.2]octane skeleton.

关键词： octane ethane skeleton

Friction and Wear Properties of High-velocity Oxygen Fuel Sprayed WC-17Co Coating under Rotational Fretting Conditions

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Chinese Journal of Mechanical Engineering 2016年第3期29卷 515-521页

作者： luo Jun CAI Zhenbing MO Jiliang PENG Jinfang ZHU Minhao Tribology Research Institute Southwest Jiaotong UniversityChengdu 610031China Engineering Research Center for Materials Protection of Wear and Corrosion of Guizhou Provincial Universities Guiyang University Guiyang 550005China

Rotational fretting which exist in many engineering applications has incurred enormous economic loss. Thus, accessible methods are urgently needed to alleviate or eliminate damage by rotational fretting. Surface engineering is an effective approach that is successfully adopted to enhance the ability of components to resist the fretting damage. In this paper, using a high-velocity oxygen fuel sprayed（HVOF） technique WC-17 Co coating is deposited on an LZ50 steel surface to study its properties through Vickers hardness testing, scanning electric microscope（SEM）, energy dispersive X-ray spectroscopy（EDX）, and X-ray diffractrometry（XRD）. Rotational fretting wear tests are conducted under normal load varied from 10 N to 50 N, and angular displacement amplitudes vary from 0.125° to 1°. Wear scars are examined using SEM, EDX, optical microscopy（OM）, and surface topography. The experimental results reveal that the WC-17 Co coating adjusted the boundary between the partial slip regime（PSR） and the slip regime（SR） to the direction of smaller amplitude displacement. As a result, the coefficients of friction are consistently lower than the substrate＇s coefficients of friction both in the PSR and SR. The damage to the coating in the PSR is very slight. In the SR, the coating exhibits higher debris removal efficiency and load-carrying capacity. The bulge is not found for the coating due to the coating＇s higher hardness to restrain plastic flow. This research could provide experimental bases for promoting industrial application of WC-17 Co coating in prevention of rotational fretting wear.

关键词： fretting wear rotational fretting WC-17Co coating LZ50 steel HVOF

Impacts of solar multiple on the performance of direct steam generation solar power tower plant with integrated thermal storage

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Frontiers in Energy 2017年第4期11卷 461-471页

作者： Yah luo Xiaoze DU Lijun YANG Chao XU Muhammad AMJAD School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 School of Mechanical and Electrical Engineering Beijing University of Chemical Technology Beijing 100029 China School of Energy Power and Mechanical Engineering North China Electric Power University Beijing 102206 China School of Chemical and Process Engineering University of Leeds Leeds LS2 9JT UK School of Energy Power and MechanicalEngineering North China Electric Power University Beijing 102206China

Solar multiple （SM） and thermal storage capacity are two key design parameters for revealing the performance of direct steam generation （DSG） solar power tower plant. In the case of settled land area, SM and thermal storage capacity can be optimized to obtain the minimum levelized cost of electricity （LCOE） by adjusting the power generation output. Taking the dual-receiver DSG solar power tower plant with a given size of solar field equivalent electricity of 100 MWe in Sevilla as a reference case, the minimum LCOE is 21.77 /kWhe with an SM of 1.7 and a thermal storage capacity of 3 h. Besides Sevilla, two other sites are also introduced to discuss the influence of annual DNI. When compared with the case of Sevilla, the minimum LCOE and optimal SM of the San Jose site change just slightly, while the minimum LCOE of the Bishop site decreases by 32.8% and the optimal SM is reduced to 1.3. The influence of the size of solar field equivalent electricity is studied as well. The minimum LCOE decreases with the size of solar field, while the optimal SM and thermal storage capacity still remain unchanged. In addition, the sensitivity of different investment in sub-system is investigated. In terms ofoptimal SM and thermal storage capacity, they can decrease with the cost of thermal storage system but increase with the cost of power generation unit.

关键词： direct steam generation solar power tower,solar multiple thermal energy storage capacity levelizedcost of electricity (LCOE)

Stego key searching for LSB steganography on JPEG decompressed image

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Science China(Information Sciences) 2016年第3期59卷 60-74页

作者： Jiufen LIU Yuguo TIAN Tao HAN Junchao WANG Xiangyang luo Zhengzhou Information Science and Technology Institute State Key Laboratory of Mathematical Engineering and Advanced Computing

At present, steganalysis research focuses on detecting the existence of a hidden message. However,extracting the hidden information, i.e., an extracting attack, is crucial in obtaining effective evidence in computer forensics. Due to the difficulty of an extracting attack, research in this field is limited. In steganography with a stego key, an extracting attack is equivalent to recovering the stego key. In this paper we study a method for recovering the stego key in least significant bit(LSB) steganography with a decompressed JPEG image as the cover image. Firstly, the recovery of the stego key is translated into a cryptanalysis problem for a sequential cipher. The method for recovering the stego key is based on estimating the modification positions. The minimum size of the data used to recover the stego key successfully is discussed. Secondly, when a decompressed JPEG image is used as the cover image, the probability of recovering the cover pixels using recompression is *** is used to compute the error of the estimated sequence. Finally, an algorithm to recover the stego key in LSB steganography with a decompressed JPEG image as the cover image is proposed. The experimental results for the steganographic software, Hide and Seek 4.1 and its variant, which is a typical representative of LSB steganography, show that the proposed method can successfully recover the stego key in LSB replacement and LSB matching, i.e., the extracting attack is successful, and it outperforms three previous methods in terms of computational complexity.

关键词： steganalysis extracting attack LSB steganography decompressed JPEG image recompression stego key

Flexible perovskite light-emitting diodes for display applications and beyond

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Journal of Semiconductors 2024年第5期45卷 8-25页

作者： Yongqi Zhang Shahbaz Ahmed Khan Dongxiang luo Guijun Li Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhen 518060China Huangpu Hydrogen Innovation Center/Guangzhou Key Laboratory for Clean Energy and Materials School of Chemistry and Chemical EngineeringGuangzhou UniversityGuangzhou 510006China

The flexible perovskite light-emitting diodes(FPeLEDs),which can be expediently integrated to portable and wearable devices,have shown great potential in various *** FPeLEDs inherit the unique optical properties of metal halide perovskites,such as tunable bandgap,narrow emission linewidth,high photoluminescence quantum yield,and particularly,the soft nature of *** present,substantial efforts have been made for FPeLEDs with encouraging external quantum efficiency(EQE)of 24.5%.Herein,we summarize the recent progress in FPeLEDs,focusing on the strategy developed for perovskite emission layers and flexible electrodes to facilitate the optoelectrical and mechanical *** addition,we present relevant applications of FPeLEDs in displays and ***,perspective toward the future development and applications of flexible PeLEDs are also discussed.

关键词： metal halide perovskite flexible light-emitting diodes optical properties mechanical flexibility display

Controllable synthesis of Li3PO4 hollow nanospheres for the preparation of high performance LiFePO4 cathode material

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Particuology 2016年第1期14卷 142-150页

作者： Jiaying Bi Tongbao Zhang Kai Wang Benhe Zhong Guangsheng luo The State Key Lab of Chemical Engineering Department of Chemical Engineering Tsinghua University Beijing 100084 China School of Chemical Engineering Sichuan University. Chengdu 610065. China

Lithium phosphate hollow nanospheres were prepared in a membrane dispersion microreactor using aqueous phosphoric acid and lithium hydroxide solutions as reactants. The influences of reactant flow rate ratio and temperature on the purity and morphology of the prepared nanospheres were investigated using X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The results showed that nanospheres prepared in the continuous flow condition had a hollow interior structure with high crystallinity. A possible mechanism for the formation of this hollow structured Li3 PO4 was also pro- posed. Using Li3 PO4 hollow nanospheres as the precursor, LiFePO4 hollow nanospheres were successfully synthesized via a solvothermal route in ethylene glycol. After coating with carbon, the LiFePO4/C hol- low nanospheres exhibited excellent electrochemical performance, especially at high rates, and could discharge124 mAh/g at 10 C, and even 98 mAh/g at 40 C.

关键词： Lithium phosphate Hollow sphere Microreactor Lithium iron phosphate

Ligand accommodation causes altered reactivity of silver clusters with iodomethane:superatomic stability of Ag_(9)I_(2)^(+)in mimicking XeF_(2)

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Science China Chemistry 2022年第8期65卷 1594-1600页

作者： Haiming Wu Mengzhou Yang Benben Huang Wen Gan Zhixun luo Beijing National Laboratory for Molecular Sciences(BNLMS) State Key Laboratory for Structural Chemistry of Unstable and Stable SpeciesInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Exploring metal cluster reactivity with alkyl halides enables to understand the related chemical mechanism of metal surfaces in terms of active *** we report a study of Ag_(n)^(+)(n=1-27)clusters reacting with iodomethane by a flow tube apparatus in tandem with a customized triple quadrupole mass *** even/odd alternation of the Ag_(n)^(+)is observed in their reactions with CH_(3)I,where silver clusters with even-number,Ag_(2n)^(+),find favorable products of Ag_(2n)I_(1,3)^(+)series,while the Ag_(2n−1)^(+)clusters form Ag_(2n−1)I_(2,4)^(+)***,Ag_(9)^(+)shows up with prominent mass abundance but allows for the formation of Ag_(9)I_(2)^(+),which finds an echo with the formation of Ag_(10)I_(3)^(+).We illustrate the enhanced stability of Ag_(9)I_(2)^(+)and Ag_(10)I_(3)^(+)by showing their significantly enlarged highest occupied molecular orbital(HOMO)-lowest unoccupied molecular orbital(LUMO)gaps and balanced charge distribution compared with the bare metal clusters,*** elucidated,is the superatomic nature of these bare and iodinated silver clusters,especially Ag_(9)I_(2)^(+)which mimics the rare-gas compound XeF_(2).This study expands a vivid example of special and general superatoms,and enriches the general knowledge on how a ligand stabilizes a metal cluster.

关键词： metal cluster superatom halide superatomic complex gas-phase reaction

The leaching of additive-derived flame retardants(FRs) from plastics in avian digestive fluids:The significant risk of highly lipophilic FRs

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Journal of Environmental Sciences 2019年第11期31卷 200-207页

作者： Huiying Guo Xiaobo Zheng Shuling Ru Xiaojun luo Bixian Mai State Key Laboratory of Organic Geochemistry and Guangdong Key Laboratory of Environmental Protection and Resources Utilization Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China College of Resources and Environment South China Agricultural University Guangzhou 510642 China University of the Chinese Academy of Sciences Beijing 100049 China

The exposure to plastic debris and associated pollutants for wildlife is of urgent concern,but little attention has been paid on the transfer of plastic additives from plastic debris to *** the present study,the leaching of incorporated flame retardants (FRs),including polybrominated diphenyl ethers (PBDEs),alternative brominated FRs (AFRs),and phosphate flame retardants (PFRs),from different sizes of recycled acrylonitrile-butadiene-styrene (ABS) polymer were investigated in avian digestive *** impact of co-ingested sediment on the leaching of additive-derived FRs in digestive fluids was also *** the recycled ABS,BDE 209 (715 μg/g) and 1,2-bis(2,4,6-tribromophenoxy) ethane (BTBPE,1766 μg/g) had the highest concentrations among all target *** leaching proportions of FRs were higher in finer sizes of *** leaching proportions of FRs from recycled ABS increased with elevated logKow of *** the tests with coexisted ABS and sediment,hexato deca-BDEs,BTBPE,and decabromodiphenyl ethane (DBDPE) migrated from ABS to sediment,which resulted in the less bioaccessible fractions of these FRs in gut *** lipophilic chemicals tended to be adsorbed by sediment from *** results suggest the migration of additive-derived FRs from plastics to other indigestible materials in digestive *** findings in this study provide insights into the transfer of additive-derived FRs from plastics to birds,and indicate the significant contribution of FR-incorporated plastics to bioaccumulation of highly lipophilic FRs.

关键词： Recycled plastics Digestive fluids Flame retardants Leaching