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Experimental study on wax deposition of highly paraffinic oil in intermittent gas-oil flow in pipelines

Petroleum Science 2024年第3期21卷 2080-2088页

作者： Chuan-Shuo Wang Qian-Li Ma Xiao-Fang Lv Jie Zhang Yang Liu shi-dong zhou Jiangsu Key Laboratory of Oil and Gas Storage and Transportation Technology Changzhou University Hade Oil and Gas Development Department Tarim Oilfield Branch

Oil-gas two phase wax deposition is a fairly common and open-ended question in flow assurance of multiphase transportation pipelines. This paper investigated the two main aspects of oil-gas two phase wax deposition layer: apparent thickness and crystal structure characteristics. A typical highly paraffinic oil in Bohai Sea, China, was used as the experimental material to investigate the wax deposition thickness in oil-gas two phase under the influence of different oil temperatures, superficial gas/liquid phase velocities and gas-oil ratios by using multiphase flow loop experimental device. Just as in the classical theory of wax molecular diffusion, it showed that wax deposition thickness of oil-gas two phase increased with increasing oil temperature. Analysis of the impact of different superficial phase velocities found that the actual liquid flow heat transfer and shear stripping was the gas phase dominant mechanisms determining wax deposit thickness. In addition, the crystal structure of the wax deposition layer was characterized with the help of small-angle X-ray scattering(SAXS) for different circumferential positions, flow rates and gas-oil ratios. The bottom deposition layer had a complex crystal structure and high hardness, which were subject to change over flow rate variations. Furthermore, the SAXS results provided evidence that the indirect effect of the actual liquid velocity modified by the gas phase was the main mechanism. Our study of the effect of gas phase on the wax deposition of oil-gas two phase will help shed light onto the mechanism by which this important process occurs. Our findings address a very urgent need in the field of wax deposition of highly paraffinic oil to understand the flow security of oilgas two phase that occurs easily in multiphase field pipelines.

关键词： Oil-gas two phase Highly paraffinic oil Wax deposition SAXS

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A Joint Activity and Data Detection Scheme for Asynchronous Grant-Free Rateless Multiple Access

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China Communications 2024年第1期21卷 34-52页

作者： Wei Zhang Xiaofeng Zhong shidong zhou Department of Electronic Engineering Tsinghua UniversityBeijing 100084China

This paper considers the frameasynchronous grant-free rateless multiple access(FAGF-RMA)scenario,where users can initiate access at any symbol time,using shared channel resources to transmit data to the base station.Rateless coding is introduced to enhance the reliability of the system.Previous literature has shown that FA-GFRMA can achieve lower access delay than framesynchronous grant-free rateless multiple access(FSGF-RMA),with extreme reliability enabled by rateless coding.To support FA-GF-RMA in more practical scenarios,a joint activity and data detection(JADD)scheme is proposed.Exploiting the feature of sporadic traffic,approximate message passing(AMP)is exploited for transmission signal matrix estimation.Then,to determine the packet start points,a maximum posterior probability(MAP)estimation problem is solved based on the recovered transmitted signals,leveraging the intrinsic power pattern in the codeword.An iterative power-pattern-aided AMP algorithm is devised to enhance the estimation performance of AMP.Simulation results verify that the proposed solution achieves a delay performance that is comparable to the performance limit of FA-GF-RMA.

关键词： asynchronous grant-free JADD rateless codes

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Community structure and species diversity dynamics of a subtropical evergreen broad-leaved forest in China:2005 to 2020

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Plant Diversity 2024年第1期46卷 70-77页

作者： shi-Guang Wei Lin Li Kun-dong Bai Zhi-Feng Wen Jing-Gang zhou Qin Lin Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection(Guangxi Normal University) Ministry of EducationGuilin 541004GuangxiChina School of Life&Environmental Sciences Guilin University of Electronic TechnologyGuilin 541004GuangxiChina Guangxi Key Laboratory of Landscape Resources Conservation and Sustainable Utilization in Lijiang River Basin Guilin 541004GuangxiChina Key Laboratory of Vegetation Restoration and Management of South China Botanical Garden of Degraded Ecosystems Chinese Academy of SciencesGuangzhou 510650GuangdongChina Center of Plant Ecology Core Botanical GardensChinese Academy of SciencesGuangzhou 510650GuangdongChina

Here,we characterize the temporal and spatial dynamics of forest community structure and species diversity in a subtropical evergreen broad-leaved forest in China.We found that community structure in this forest changed over a 15-year period.Specifically,renewal and death of common species was large,with the renewal of individuals mainly concentrated within a few populations,especially those of Aidia canthioides and Cryptocarya concinna.The numbers of individual deaths for common species were concentrated in the small and mid-diameter level.The spatial distribution of community species diversity fluctuated in each monitoring period,showing a more dispersed diversity after the 15-year study period,and the coefficient of variation on quadrats increased.In 2010,the death and renewal of the community and the spatial variation of species diversity were different compared to other survey years.Extreme weather may have affected species regeneration and community stability in our subtropical monsoon evergreen broad-leaved forests.Our findings suggest that strengthening the monitoring and management of the forest community will help better understand the long-and short-term causes of dynamic fluctuations of community structure and species diversity,and reveal the factors that drive changes in community structure.

关键词： Community structure Death and renewal dynamics Species diversity dynamics South subtropical forest

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Two-Staged Method for Ice Channel Identification Based on Image Segmentation and Corner Point Regression

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China Ocean Engineering 2024年第2期38卷 313-325页

作者： dong Wen-bo zhou Li DING shi-feng WANG Ai-ming CAI Jin-yan School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212003China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China

Identification of the ice channel is the basic technology for developing intelligent ships in ice-covered waters,which is important to ensure the safety and economy of navigation.In the Arctic,merchant ships with low ice class often navigate in channels opened up by icebreakers.Navigation in the ice channel often depends on good maneuverability skills and abundant experience from the captain to a large extent.The ship may get stuck if steered into ice fields off the channel.Under this circumstance,it is very important to study how to identify the boundary lines of ice channels with a reliable method.In this paper,a two-staged ice channel identification method is developed based on image segmentation and corner point regression.The first stage employs the image segmentation method to extract channel regions.In the second stage,an intelligent corner regression network is proposed to extract the channel boundary lines from the channel region.A non-intelligent angle-based filtering and clustering method is proposed and compared with corner point regression network.The training and evaluation of the segmentation method and corner regression network are carried out on the synthetic and real ice channel dataset.The evaluation results show that the accuracy of the method using the corner point regression network in the second stage is achieved as high as 73.33%on the synthetic ice channel dataset and 70.66%on the real ice channel dataset,and the processing speed can reach up to 14.58frames per second.

关键词： ice channel ship navigation identification image segmentation corner point regression

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Physiological and pathological functions of circular RNAs in the nervous system

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Neural Regeneration Research 2024年第2期19卷 342-349页

作者： Min zhou shi Li Chuan Huang School of Life Sciences Chongqing UniversityChongqingChina

Circular RNAs(circRNAs)are a class of covalently closed single-stranded RNAs that are expressed during the development of specific cells and tissues.CircRNAs play crucial roles in physiological and pathological processes by sponging microRNAs,modulating gene transcription,controlling the activity of certain RNA-binding proteins,and producing functional peptides.A key focus of research at present is the functionality of circRNAs in the nervous system and several advances have emerged over the last 2 years.However,the precise role of circRNAs in the nervous system has yet to be comprehensively reviewed.In this review,we first summarize the recently described roles of circRNAs in brain development,maturity,and aging.Then,we focus on the involvement of circRNAs in various diseases of the central nervous system,such as brain cancer,chronic neurodegenerative diseases,acute injuries of the nervous system,and neuropathic pain.A better understanding of the functionality of circRNAs will help us to develop potential diagnostic,prognostic,and therapeutic strategies to treat diseases of the nervous system.

关键词： Alzheimer’s disease amyotrophic lateral sclerosis brain development circRNAs neuropathic pain Parkinson’s disease

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Internal Polarization Field Induced Hydroxyl Spillover Effect for Industrial Water Splitting Electrolyzers

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Nano-Micro Letters 2024年第2期16卷 438-449页

作者： Jingyi Xie Fuli Wang Yanan zhou Yiwen dong Yongming Chai Bin dong State Key Laboratory of Heavy Oil Processing College of Chemistry and Chemical EngineeringChina University of Petroleum(East China)Qingdao 266580People’s Republic of China

The formation of multiple oxygen intermediates supporting efficient oxygen evolution reaction(OER)are affinitive with hydroxyl adsorption.However,ability of the catalyst to capture hydroxyl and maintain the continuous supply at active sits remains a tremendous challenge.Herein,an affordable Ni2P/FeP2 heterostructure is presented to form the internal polarization field(IPF),arising hydroxyl spillover(HOSo)during OER.Facilitated by IPF,the oriented HOSo from FeP2 to Ni2P can activate the Ni site with a new hydroxyl transmission channel and build the optimized reaction path of oxygen intermediates for lower adsorption energy,boosting the OER activity(242 mV vs.RHE at 100 mA cm-2)for least 100 h.More interestingly,for the anion exchange membrane water electrolyzer(AEMWE)with low concentration electrolyte,the advantage of HOSo effect is significantly amplified,delivering 1 A cm^(-2)at a low cell voltage of 1.88 V with excellent stability for over 50 h.

关键词： Hydroxyl spillover effect Internal polarization field Heterostructure Oxygen reduction reaction Anion exchange membrane water electrolysis

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Low-noise and low-power pixel sensor chip for gas pixel detectors

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Nuclear Science and Techniques 2024年第3期35卷 142-152页

作者： Zhuo zhou shi-Qiang zhou dong Wang Xiang-Ming Sun Chao-Song Gao Peng-Zhen Zhu Wei-Ping Ren Jun Liu Mu-Xian Li Chen Lian Chun-Lai dong PLAC Key Laboratory of Quark and Lepton Physics(MOE)Central China Normal UniversityWuhan 430079China

Topmetal-M2 is a large-area pixel sensor chip fabricated using the GSMC 130 nm CMOS process in 2021.The pixel array of Topmetal-M2 consists of pixels of 400 rows×512 columns with a pixel pitch of 45μm×45μm.The array is divided into 16 subarrays,with pixels of 400 rows×32 columns per subarray.Each pixel incorporates two charge sensors:a diode sensor and a Topmetal sensor.The in-pixel circuit primarily consists of a charge-sensitive amplifier for energy measurements,a discriminator with a peak-holding circuit,and a time-to-amplitude converter for time-of-arrival measurements.The pixel of Topmetal-M2 has a charge input range of~0-3 k e-,a voltage output range of~0-180 mV,and a charge-voltage conversion gain of~59.56μV∕e-.The average equivalent noise charge of Topmetal-M2,which includes the readout electronic system noise,is~43.45 e-.In the scanning mode,the time resolution of Topmetal-M2 is 1 LSB=1.25μs,and the precision is^()7.41μs.At an operating voltage of 1.5 V,Topmetal-M2 has a power consumption of~49 mW∕cm~2.In this article,we provide a comprehensive overview of the chip architecture,pixel working principles,and functional behavior of Topmetal-M2.Furthermore,we present the results of preliminary tests conducted on Topmetal-M2,namely,alpha-particle and soft X-ray tests.

关键词： Charge collection Gas detectors Semiconductor detectors X-ray detectors

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Projections of summer light rain frequency in typical terrain over eastern China under wind speed constraint

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Science China Earth Sciences 2024年第6期67卷 1885-1894页

作者： Xuechen dong Daoyi GONG Cuicui shi Institute of Disaster Risk Science Faculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China Key Laboratory of Environmental Change and Natural Disaster MOEFaculty of Geographical ScienceBeijing Normal UniversityBeijing 100875China School of National Safety and Emergency Management Beijing Normal UniversityBeijing 100875China School of Systems Science Beijing Normal UniversityBeijing 100875China

The variation in near-surface wind speed is a key dynamic parameter in the orographic effect of precipitation over eastern China.In this study,we used the latest high-resolution outputs from six GCMs in CMIP6-HighResMIP to evaluate the performance of high-resolution models in simulating the orographic precipitation characteristics of typical mountainous areas in summer over eastern China.The orographic precipitation under warming scenarios was projected and constrained according to observational data.The results indicated that during the contemporary climate reference period(1979-2009),although the relationship between model-simulated near-surface wind speed and orographic light rain frequency was consistently stable,the sensitivity of the orographic light rain frequency to surface wind variability was generally underestimated,with a deviation approximately 24.1% lower than the observational values.The estimated orographic light rain frequency corrected based on the observed near-surface wind speed under a 1.5℃ warming scenario,was 36.1% lower than that of the contemporary period;this reduction was 8.6 times that without the wind speed constraint(4.2%).The MRI-AGCM3-2-S model,with a longer dataset,demonstrated relatively stable reductions in orographic light rain frequency under different warming scenarios(1.5℃,2℃,3℃,and 4℃)after the application of wind speed constraints.In all cases,the reductions exceeded those for the predictions made without the wind speed constraint.

关键词： Frequency of orographic light rain HighResMIP High-resolution projection Observational constraint Eastern China

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The roles of RACK1 in the pathogenesis of Alzheimer's disease

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Journal of Biomedical Research 2024年第2期38卷 137-148页

作者： Wenting He Xiuyu shi Zhifang dong Pediatric Research Institute Ministry of Education Key Laboratory of Child Development and DisordersNational Clinical Research Center for Child Health and DisordersChongqing Key Laboratory of Child Neurodevelopment and Cognitive DisordersChildren's Hospital of Chongqing Medical UniversityChongqing 400014China

The receptor for activated C kinase 1(RACK1)is a protein that plays a crucial role in various signaling pathways and is involved in the pathogenesis of Alzheimer's disease(AD),a prevalent neurodegenerative disease.RACK1 is highly expressed in neuronal cells of the central nervous system and regulates the pathogenesis of AD.Specifically,RACK1 is involved in regulation of the amyloid-β precursor protein processing through α-or β-secretase by binding to different protein kinase C isoforms.Additionally,RACK1 promotes synaptogenesis and synaptic plasticity by inhibiting N-methyl-D-aspartate receptors and activating gamma-aminobutyric acid A receptors,thereby preventing neuronal excitotoxicity.RACK1 also assembles inflammasomes that are involved in various neuroinflammatory pathways,such as nuclear factor-kappa B,tumor necrosis factor-alpha,and NOD-like receptor family pyrin domain-containing 3 pathways.The potential to design therapeutics that block amyloid-β accumulation and inflammation or precisely regulate synaptic plasticity represents an attractive therapeutic strategy,in which RACK1 is a potential target.In this review,we summarize the contribution of RACK1 to the pathogenesis of AD and its potential as a therapeutic target.

关键词： RACK1 Alzheimer's disease PKC amyloid-β synaptic plasticity neuroinflammation

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Endomembrane-biased dimerization of ABCG16 and ABCG25 transporters determines their substrate selectivity in ABA-regulated plant growth and stress responses

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Molecular Plant 2024年第3期17卷 478-495页

作者： Yeling zhou Yuzhu Wang dong Zhang Jiansheng Liang institute of Plant and Food Science Department of BiologySchool of Life SciencesSouthern University of Science and Technology(SUSTech)Shenzhen 518055China Key Laboratory of Molecular Design for Plant Cell Factory of Guangdong Higher Education Institutes Southern University of Science and Technology(SUSTech)Shenzhen 518055China jiangsu Key Laboratory of Crop Genetics and Physiology/Co-lnnovation Center for Modern Production Technology of Grain Crops Key Laboratory of Plant Functional Genomics of the Ministry of EducationYangzhou UniversityYangzhou 225009China

ATP-binding cassette(ABC)transporters are integral membrane proteins that have evolved diverse func-tions fulfilled via the transport of various substrates.In Arabidopsis,the G subfamily of ABC proteins is particularly abundant and participates in multiple signaling pathways during plant development and stress responses.In this study,we revealed that two Arabidopsis ABCG transporters,ABCG16 and ABCG25,engage in ABA-mediated stress responses and early plant growth through endomembrane-specific dimerization-coupled transport of ABA and ABA-glucosyl ester(ABA-GE),respectively.We first revealed that ABCG16 contributes to osmotic stress tolerance via ABA signaling.More specifically,ABCG16 induces cellular ABA efflux in both yeast and plant cells.Using FRET analysis,we showed that ABCG16 forms oblig-atory homodimers for ABA export activity and that the plasma membrane-resident ABCG16 homodimers specifically respond to ABA,undergoing notable conformational changes.Furthermore,we demonstrated that ABCG16 heterodimerizes with ABCG25 at the endoplasmic reticulum(ER)membrane and facilitates the ER entry of ABA-GE in both Arabidopsis and tobacco cells.The specific responsiveness of the ABCG16-ABCG25 heterodimer to ABA-GE and the superior growth of their double mutant support an inhib-itory role of these twoABCGs in early seedling establishment via regulation of ABA-GE translocation across the ER membrane.Our endomembrane-specific analysis of the FRET signals derived from the homo-or heterodimerized ABcG complexes allowed us to link endomembrane-biased dimerization to the transloca-tion of distinct substrates by ABcG transporters,providing a prototypic framework for understanding the omnipotence of ABcG transporters in plant development and stress responses.

关键词： abscisic acid ABCG transporter dimerization endomembrane substrate selectivity

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