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基于数值模拟的低温风洞羽流扩散过程的参数敏感性分析（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2018年第10期19卷 746-757页

作者： jing-feng li Kai WANG Xiao-bin ZHANG Xia ZHOU li-min QIU Institute of Refrigeration and Cryogenics Zhejiang University Department of Chemical Engineering Imperial College London

目的:低温风洞运行时大流量低温氮气被排放到大气环境中,对周围环境造成潜在的低温、缺氧危险。本文旨在研究羽流扩散过程中各变量(环境风速、环境风温度、相对湿度和排气出口流速)对羽流沉降的影响。创新点:采用考虑相变的低温羽流扩... 详细信息

目的:低温风洞运行时大流量低温氮气被排放到大气环境中,对周围环境造成潜在的低温、缺氧危险。本文旨在研究羽流扩散过程中各变量(环境风速、环境风温度、相对湿度和排气出口流速)对羽流沉降的影响。创新点:采用考虑相变的低温羽流扩散模型,通过数值模拟对影响羽流扩散的各参数进行敏感性分析。方法:1.基于Hertz-Knudsen关系修正,考虑空气中水的相变,构建低温羽流扩散的数值模型;2.对照美国National TransonicFacility的羽流扩散数据和NASA的二阶分析模型的计算结果,验证本文所采用的数值模型的准确性;3.利用数值模拟,比较不同排放条件下近地面的最低氧含量和最低温度,并对各变量进行敏感性分析。结论:1.考虑相变的羽流扩散数值模型,相比NASA的二阶分析模型拥有更好的准确性。2.对于0.3m低温风洞的羽流扩散,高环境风速有利于羽流消散;高环境温度和高相对湿度能提升近地面的最低温度,但对近地面的最低氧含量影响甚微。3.当排气速度小于2 kg/s时,排气流速增大不利于羽流消散;当羽流速度大于2 kg/s时,排气流速增大有利于羽流消散。

关键词：低温风洞羽流扩散计算流体动力学相变

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Determination of polarization states in(K,Na)NbO3 lead-free piezoelectric crystal

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Journal of Advanced Ceramics 2020年第2期9卷 204-209页

作者： Mao-Hua ZHANG Chengpeng HU Zhen ZHOU Hao TIAN Hao-Cheng THONG Yi Xuan liU Xing-Yu XU Xiao-Qing XI jing-feng li Ke WANG State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China Department of Physics Harbin Institute of TechnologyHarbin 150001China

Polarization switching in lead-free(K0.40Na0.60)NbO3(KNN)single crystals was studied by switching spectroscopy piezoresponse force microscopy(SS-PFM).Acquisition of multiple hysteresis loops on a closely spaced square grid enables polarization switching parameters to be mapped in real space.Piezoresponse amplitude and phase hysteresis loops show collective symmetric/asymmetric characteristics,affording information regarding the switching behavior of different domains.As such,the out-of-plane polarization states of the domains,including amplitudes and phases can be determined.Our results could contribute to a further understanding of the relationships between polarization switching and polarization vectors at the nanoscale,and provide a feasible method to correlate the polarization hysteresis loops in a domain under an electric field with the polarization vector states.

关键词： piezoelectrics lead-free (K0.40Na0.60)NbO3(KNN) switching spectroscopy piezoresponse force microscopy(SS-PFM) ferroelectric domain

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Highly Textured N-Type SnSe Polycrystals with Enhanced Thermoelectric Performance

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Research 2019年第1期2019卷 251-260页

作者： Peng-Peng Shang Jinfeng Dong Jun Pei Fu-Hua Sun Yu Pan Huaichao Tang Bo-Ping Zhang li-Dong Zhao jing-feng li State Key Laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing 100084China College of Chemistry and Material Science Shandong Agricultural UniversityTai’an 271018China The Beijing Municipal Key Laboratory of New Energy Materials and Technologies School of Materials Science and EngineeringUniversity of Science and Technology BeijingBeijing 100083China School of Materials Science and Engineering Beihang UniversityBeijing 100191China

Thermoelectric materials,which directly convert heat into electricity based on the Seebeck effects,have long been investigated for use in semiconductor refrigeration or waste heat recovery.Among them,SnSe has attracted significant attention due to its promising performance in both p-type and n-type crystals;in particular,a higher out-of-plane ZT value could be achieved in ntype SnSe due to its 3D charge and 2D phonon transports.In this work,the thermoelectric transport properties of n-type polycrystalline SnSe were investigated with an emphasis on the out-of-plane transport through producing textural microstructure.The textures were fabricated using mechanical alloying and repeated spark plasma sintering(SPS),as a kind of hot pressing,aimed at producing strong anisotropic transports in n-type polycrystalline SnSe as that in crystalline SnSe.Results show that the lowest thermal conductivity of 0.36 Wm^(-1) K^(-1) was obtained at 783 K in perpendicular to texture direction.Interestingly,the electrical transport properties are less anisotropic and even nearly isotropic,and the power factors reach 681.3μWm^(-1) K^(-2) at 783 K along both parallel and perpendicular directions.The combination of large isotropic power factor and low anisotropic thermal conductivity leads to a maximum ZT of 1.5 at 783 K.The high performance elucidates the outstanding electrical and thermal transport behaviors in n-type polycrystalline SnSe,and a higher thermoelectric performance can be expected with future optimizing texture in n-type polycrystalline SnSe.

关键词： alloying polycrystalline anisotropic

Effect of low-degree astigmatism on the objective visual quality

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International Journal of Ophthalmology(English edition) 2024年第6期17卷 1086-1093页

作者： ling-Ying Ye Shu-feng li jing-jing Zuo Jin li Hui-Xiang Ma National Clinical Research Center for Ocular Diseases Eye HospitalWenzhou Medical UniversityWenzhou 325027Zhejiang ProvinceChina

AIM:To evaluate the effect of low-degree astigmatism on objective visual quality through the Optical Quality Analysis System(OQAS).METHODS:This study enrolled 46 participants(aged 23 to 30y,90 eyes)with normal or corrected-to-normal vision.The cylindrical lenses(0,0.5,0.75,1.0,and 1.25 D)were placed at the axial direction(180°,45°,90°,and 135°)in front of the eyes with the best correction to form 16 types of regular low-degree astigmatism.OQAS was used to detect the objective visual quality,recorded as the objective scattering index(OSI),OQAS values at contrasts of 100%,20%,and 9%predictive visual acuity(OV100%,OV20%,and OV9%),modulation transfer function cut-off(MTFcut-off)and Strehl ratio(SR).The mixed effect linear model was used to compare objective visual quality differences between groups and examine associations between astigmatic magnitude and objective visual quality parameters.RESULTS:Apparent negative relationships between the magnitude of low astigmatism and objective visual quality were observed.The increase of OSI per degree of astigmatism at 180°,45°,90°,and 135°axis were 0.38(95%CI:0.35,0.42),0.50(95%CI:0.46,0.53),0.49(95%CI:0.45,0.54)and 0.37(95%CI:0.34,0.41),respectively.The decrease of MTFcut-off per degree of astigmatism at 180°,45°,90°,and 135°axis were-10.30(95%CI:-11.43,-9.16),-12.73(95%CI:-13.62,-11.86),-12.75(95%CI:-13.79,-11.70),and-9.97(95%CI:-10.92,-9.03),respectively.At the same astigmatism degree,OSI at 45°and 90°axis were higher than that at 0°and 135°axis,while MTFcut-off were lower.CONCLUSION:Low astigmatism of only 0.50 D can significantly reduce the objective visual quality.

关键词： low-degree astigmatism objective visual quality Optical Quality Analysis System

Adenylate cyclase activates the cAMP signalling pathway to enhance platelet-rich plasma-treated Achilles tendon disease,a theoretical bioinformatics-based study

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World Journal of Orthopedics 2024年第2期15卷 192-200页

作者： jing-Yi Sun Cai li feng-Ying Du College of Basic Medical Science Qilu Medical UniversityZibo 255300Shandong ProvinceChina Department of Gastroenterological Surgery Shandong Provincial Hospital of Shandong First Medical UniversityJinan 250021Shandong ProvinceChina

The effectiveness of platelet-rich plasma(PRP)for the treatment of Achilles tendon disorders still needs to be evaluated through a series of prospective studies,but genomic analysis can reveal the existence of complementary PRP treatment options.Based on the 96 platelet activation-related genes in the Kyoto Encyclopedia of Genes and Genomes(KEGG)database,we performed Gene Ontology functional enrichment analysis and KEGG enrichment analysis,pathway correlation analysis,and enrichment mapping to determine the enrichment results of the gene set enrichment analysis and found that the cAMP signalling pathway may be the key to enhancing the effectiveness of PRP treatment.The cAMP signalling pathway interacts with the Rap1 signalling pathway and cGMPPKG signalling pathway to mediate the entire pathophy-siological process of Achilles tendon disease.Moreover,ADCY1-9 may be the key to the activation of the cAMP signalling network.Further based on the data in the Gene Expression Omnibus database,it was found that ADCY4 and ADCY7 may be the players that play a major role,associated with the STAT4-ADCY4-LAMA5 axis and the GRbeta-ADCY7-SEMA3C axis,which is expected to be a complementary target for enhancing the efficacy of PRP in the treatment of Achilles tendon disease.

关键词： Platelet-rich plasma Achilles tendon disease cAMP Adenylate cyclase Complementary target

Exploring the Cation Regulation Mechanism for Interfacial Water Involved in the Hydrogen Evolution Reaction by In Situ Raman Spectroscopy

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Nano-Micro Letters 2024年第3期16卷 303-312页

作者： Xueqiu You Dongao Zhang Xia‑Guang Zhang Xiangyu li jing‑Hua Tian Yao‑Hui Wang Jian‑feng li School of Ocean Information Engineering Fujian Provincial Key Laboratory of Oceanic Information Perception and Intelligent ProcessingJimei UniversityXiamen 361021People’s Republic of China State Key Laboratory of Physical Chemistry of Solid Surfaces MOE Key Laboratory of Spectrochemical Analysis and InstrumentationiChEMCollege of Chemistry and Chemical EngineeringCollege of MaterialsCollege of EnergyXiamen UniversityXiamen 361005People’s Republic of China Key Laboratory of Green Chemical Media and Reactions Ministry of EducationCollaborative Innovation Center of Henan Province for Green Manufacturing of Fine ChemicalsCollege of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiang 453007People’s Republic of China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen 361005People’s Republic of China

Interfacial water molecules are the most important participants in the hydrogen evolution reaction(HER).Hence,understanding the behavior and role that interfacial water plays will ultimately reveal the HER mechanism.Unfortunately,investigating interfacial water is extremely challenging owing to the interference caused by bulk water molecules and complexity of the interfacial environment.Here,the behaviors of interfacial water in different cationic electrolytes on Pd surfaces were investigated by the electrochemistry,in situ core-shell nanostructure enhanced Raman spectroscopy and theoretical simulation techniques.Direct spectral evidence reveals a red shift in the frequency and a decrease in the intensity of interfacial water as the potential is shifted in the positively direction.When comparing the different cation electrolyte systems at a given potential,the frequency of the interfacial water peak increases in the specified order:li+

关键词： In situ Raman Interfacial water Hydrogen evolution reaction Cations

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Assessment of cheese sign and its association with vascular risk factors: Data from PUMCH dementia cohort

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中华医学杂志(英文版) 2024年第7期137卷 830-836页

作者： Huang Xinying Hou Bo Wang Jie li Jie Shang li Mao Chenhui Dong liling liu Caiyan feng feng Gao jing Peng Bin Department of Neurology State Key Laboratory of Complex Severe and Rare Disease Peking Union Medical College Hospital Chinese Academy of Medical Science and Peking Union Medical College Beijing 100730 China Department of Radiology Chinese Academy of Medical Sciences and Peking Union Medical College

Background: In the clinic, practitioners encounter many patients with an abnormal pattern of dense punctate magnetic resonance imaging (MRI) signal in the basal ganglia, a phenomenon known as "cheese sign". This sign is reported as common in cerebrovascular diseases, dementia, and old age. Recently, cheese sign has been speculated to consist of dense perivascular space (PVS). This study aimed to assess the lesion types of cheese sign and analyze the correlation between this sign and vascular disease risk factors.Methods: A total of 812 patients from Peking Union Medical College Hospital (PUMCH) dementia cohort were enrolled. We analyzed the relationship between cheese sign and vascular risk. For assessing cheese sign and defining its degree, the abnormal punctate signals were classified into basal ganglia hyperintensity (BGH), PVS, lacunae/infarctions and microbleeds, and counted separately. Each type of lesion was rated on a four-level scale, and then the sum was calculated; this total was defined as the cheese sign score. Fazekas and Age-Related White Matter Changes (ARWMC) scores were used to evaluate the paraventricular, deep, and subcortical gray/white matter hyperintensities.Results: A total of 118 patients (14.5%) in this dementia cohort were found to have cheese sign. Age (odds ratio [OR]: 1.090, 95% confidence interval [CI]: 1.064-1.120,P lipidemia, and cheese sign. The main components of cheese sign were BGH, PVS, and lacunae/infarction. The proportion of PVS increased with cheese sign severity.Conclusions: The risk factors for cheese sign were hypertension, age, and stroke. Cheese sign consists of BGH, PVS, and lacunae/infarction.

关键词： Dementia Cerebrovascular disease Cheese sign Dense punctate lesions Basal ganglia Risk factor White matter

Neuroimaging features in a patient with non-ketotic hyperglycaemic seizures: A case report

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World Journal of Clinical Cases 2024年第5期12卷 1004-1009页

作者： jing Wu Huijie feng Yaxiong Zhao Junfeng li Ting li Kefeng li Department of Radiology Heping Hospital Affiliated to Changzhi Medical CollegeChangzhi 046000Shanxi ProvinceChina Changzhi Key Lab of Functional Imaging for Brain Diseases Heping Hospital Affiliated to Changzhi Medical CollegeChangzhi 046000Shanxi ProvinceChina Faculty of Applied Sciences Macao Polytechnic UniversityMacao 999078China

BACKGROUND Non-ketotic hyperglycaemic(NKH)seizures are a rare neurological complication of diabetes caused by hyperglycaemia in non-ketotic and non-hyperosmotic states.The clinical characteristics of NKH seizures are atypical and lack unified diagnostic criteria,leading to potential misdiagnoses in the early stages of the disease.CASE SUMMARY This report presents a rare case of NKH seizures in a 52-year-old male patient with a history of type 2 diabetes mellitus.We performed comprehensive magnetic resonance imaging(MRI)studies at admission,12 d post-admission,and 20 d post-discharge.The imaging techniques included contrast-enhanced head MRI,T2-weighted imaging(T2WI),fluid-attenuated inversion recovery(FLAIR),diffusion-weighted imaging,susceptibility-weighted imaging,magnetic reso-nance spectroscopy(MRS),and magnetic resonance venography.At the time of admission,T2WI and FLAIR of the cranial MRI showed that the left parieto-occipital cortex had gyrus-like swelling and high signal,and subcortical stripes had low signal.MRS showed a reduced N-acetylaspartate peak and increased creatine and choline peaks in the affected areas.A follow-up MRI 20 d later showed that the swelling and high signal of the left parieto-occipital cortex had disappeared,and the low signal of the subcortex had disappeared.CONCLUSION This case study provides valuable insights into the potential pathogenesis,diagnosis,and treatment of NKH seizures.The comprehensive MRI findings highlight the potential utility of various MRI sequences in diagnosing and characterizing NKH seizures.

关键词： Non-ketotic hyperglycaemia seizures Magnetic resonance imaging Magnetic resonance spectroscopy Diabetes Case report

The infection kinetics and transmission potential of two Guaico Culex viruses in Culex quinquefasciatus mosquitoes

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Virologica Sinica 2024年第2期39卷 228-234页

作者： Ru-Yi Chen Teng Zhao jing-jing Guo feng Zhu Na-Na Zhang Xiao-feng li Hai-Tao liu Fei Wang Yong-Qiang Deng Cheng-feng Qin College of Bioscience and Bioengineering Jiangxi Agricultural UniversityNanchang330045China State Key Laboratory of Pathogen and Biosecurity Beijing Institute of Microbiology and EpidemiologyAMMSBeijing100071China School of life Sciences Southwest Forestry UniversityKunming650224China

Guaico Culex virus(GCXV)is a newly identified segmented jingmenvirus from Culex spp.mosquitoes in Central and South America.The genome of GCXV is composed of four or five single-stranded positive RNA segments.However,the infection kinetics and transmission capability of GCXV in mosquitoes remain unknown.In this study,we used reverse genetics to rescue two GCXVs(4S and 5S)that contained four and five RNA segments,respectively,in C6/36 cells.Further in vitro characterization revealed that the two GCXVs exhibited comparable replication kinetics,protein expression and viral titers.Importantly,GCXV RNAs were detected in the bodies,salivary glands,midguts and ovaries of Culex quinquefasciatus at 4–10 days after oral infection.In addition,two GCXVs can colonize Cx.quinquefasciatus eggs,resulting in positive rates of 15%–35%for the second gonotrophic cycle.In conclusion,our results demonstrated that GCXVs with four or five RNA segments can be detected in Cx.quinquefasciatus eggs during the first and second gonotrophic cycles after oral infection.

关键词： Guaico Culex virus(GCXV) jingmenvirus Culex quinquefasciatus Vertical transmission