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Flow characteristic of polymer solutions in porous media:Influence of the molecular weight and concentration

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Petroleum 2023年第2期9卷 214-222页

作者： Yingjie Dai Jia Li Li Li yifei Liu Yuan Li Xiangyu Wang Xuguang song Caili Dai Bin Yuan Key Laboratory of Unconventional Oil&Gas Development(China University of Petroleum East China)Ministry of EducationQingdao 266580China Shandong Key Laboratory of Oilfield Chemistry(China University of Petroleum East China)Qingdao 266580China Nanchong Vocational and Technical College Nanchong 637131China Oil&Gas Technology Research Institute of Changqing Oilfield Company Xi'an 710000China Sinopec Research Institute of Petroleum Engineering Fracturing&Acidizing and Natural Gas Production Research InstituteDongying 257000China Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 1H9Canada

The polymer solution flow in porous media is a central research topic related to hydraulic fracturing measures,formation damage and fracture *** by molecular weights and concentrations,various flow patterns of polymer in pores are presented,resulting in different filtration *** this work,the effectiveness of various polymer solutions for filtration loss was assessed by utilizing the core flooding experiment *** result shows that lesser filtration loss normally is inextricably linked to solutions with high molecular weight and ***,the flow behaviors of polymer solutions investigated by designed micro pore-throat structure and micro-particle image velocimetry(m-PIV)further confirmed the above *** was found that the central convergent flow pattern benefiting from higher viscous force loss and less filtration loss was observed at high flow rates(0.5 mL/h),and higher molecular weight and concentration were more prone to convergent flow *** viscosity force loss increases by about 4 times varying the molecular weight of polymer from 5×10^(6)to 18×10^(6)g/mol or the concentration from 0.05 to 0.3%.It interprets higher molecular weight and concentration in core studies and field observations with decreased filtration loss of *** work provides a theoretical foundation for the application of fracturing fluids as well as fresh perspectives on how to access the filtration loss of fracturing fluids.

关键词： Polymer solution Porous media Flow pattern m-PIV

SAMD4 family members suppress human hepatitis B virus by directly binding to the Smaug recognition region of viral RNA

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Cellular & Molecular Immunology 2021年第4期18卷 1032-1044页

作者： Yuze Wang Xinrui Fan Yunlong song yifei Liu Ruixin Liu Jianfeng Wu Xiaoling Li Quan Yuan Guo Fu Ningshao Xia Jiahuai Han State Key Laboratory of Cellular Stress Biology Innovation Center for Cell Signaling NetworkSchool of Life SciencesXiamen UniversityXiamenFujian 361102China State Key Laboratory of Molecular Vaccinology and Molecular Diagnostics National Institute of Diagnostics and Vaccine Development in Infectious DiseasesSchool of Public HealthXiamen UniversityXiamenFujian 361005China Cancer Research Center of Xiamen University Xianmen Hospital of Xiamen UniversitySchool of MedicineXiamen UniversityXiamenFujian 361102China

HBV infection initiates hepatitis B and promotes liver cirrhosis and hepatocellular ***-α is commonly used in hepatitis B therapy,but how it inhibits HBV is not fully *** screened 285 human interferon-stimulated genes(ISGs)for anti-HBV activity using a cell-based assay,which revealed several anti-HBV *** these ISGs,SAMD4A was the strongest suppressor of HBV *** found the binding site of SAMD4A in HBV RNA,which was a previously unidentified Smaug recognition region(SRE)sequence conserved in HBV ***4A binds to the SRE site in viral RNA to trigger its *** SAM domain in SAMD4A is critical for RNA binding and the C-terminal domain of SAMD4A is required for SAMD4A anti-HBV *** SAMD4B is a homolog of human SAMD4A but is not an ISG,and the murine genome encodes *** these SAMD4 proteins suppressed HBV replication when overexpressed in vitro and in *** also showed that knocking out the Samd4 gene in hepatocytes led to a higher level of HBV replication in mice and AAV-delivered SAMD4A expression reduced the virus titer in HBVproducing transgenic *** addition,a database analysis revealed a negative correlation between the levels of SAMD4A/B and HBV in *** data suggest that SAMD4A is an important anti-HBV ISG for use in IFN therapy of hepatitis B and that the levels of SAMD4A/B expression are related to HBV sensitivity in humans.

关键词： ISG Hepatitis B virus SAMD4 family proteins RNA degradation

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人为干扰对黄河湿地植物群落的影响及其机制

郑州大学学报（工学版） 2024年第4期45卷 102-110页

作者：万俊锋宋一帆郭林马逸飞李哲丁俊祥郭笑盈郑州大学生态与环境学院河南郑州450001 河南省环境与资源国际联合实验室河南郑州450001 河南省地质研究院河南郑州450001

为了分析人为干扰类型对黄河湿地植物群落的影响差异及相关作用机制,在进行大量实地调查后,选择郑州段3个分别受农业种植、水库修建、建筑施工干扰下的湿地为对象,在对植物群落与相关环境因子指标进行测定后,结合人类压力指标评价体系... 详细信息

为了分析人为干扰类型对黄河湿地植物群落的影响差异及相关作用机制,在进行大量实地调查后,选择郑州段3个分别受农业种植、水库修建、建筑施工干扰下的湿地为对象,在对植物群落与相关环境因子指标进行测定后,结合人类压力指标评价体系进行冗余分析。结果表明:研究区湿地植物群落整体表现出明显的退化趋势,维持湿地生产力的内在功能降低;对于不同人为干扰类型下的样地,受到人为干扰的严重程度从大到小依次为建筑施工类干扰、农业种植类干扰、水库修建类干扰;随着人为干扰严重程度的加剧,不同湿地植物群落相似性系数依次下降,鸟类栖息地湿地和太平庄北湿地的物种丰富度指数较桃花峪湿地相比下降程度分别为15.98%和37.05%,整体湿地植物群落构建逐渐趋于简单化;在引起湿地退化的诸多因素中,土壤中铵态氮含量改变对物种多样性指数与物种均匀度指数呈显著负相关,是湿地植物退化的主要原因之一。

关键词：黄河湿地退化机制植物群落人为干扰评价冗余分析

脑卒中偏瘫患者下肢深静脉血栓的发生情况及其危险因素分析

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血管与腔内血管外科杂志 2024年第3期10卷 357-361页

作者：王云鑫宋宇周立华黄欢欢潘易飞哈尔滨医科大学附属第一医院神经内科黑龙江哈尔滨150000 哈尔滨医科大学附属第一医院血管外科黑龙江哈尔滨150000

目的探讨脑卒中偏瘫患者下肢深静脉血栓(DVT)的发生情况及其危险因素。方法收集2021年1月至2022年12月于哈尔滨医科大学附属第一医院住院接受治疗的106例脑卒中偏瘫患者的临床资料,按照是否发生下肢DVT将患者分为DVT组(n=39)和对照组(... 详细信息

目的探讨脑卒中偏瘫患者下肢深静脉血栓(DVT)的发生情况及其危险因素。方法收集2021年1月至2022年12月于哈尔滨医科大学附属第一医院住院接受治疗的106例脑卒中偏瘫患者的临床资料,按照是否发生下肢DVT将患者分为DVT组(n=39)和对照组(n=67)。比较两组患者的临床特征、脑卒中病情,分析脑卒中偏瘫患者下肢DVT发生情况的危险因素。结果 DVT组患者的年龄大于对照组患者,吸烟史比例、D-二聚体水平、偏瘫时间≥1 d的比例、患肢肌力﹤3级的比例均高于对照组患者,差异均有统计学意义(P﹤0.05)。多因素分析结果显示,年龄≥65岁、有吸烟史、偏瘫时间≥1 d、D-二聚体水平≥500μg/L及患肢肌力﹤3级均为脑卒中偏瘫患者发生下肢DVT的独立危险因素(P﹤0.05)。结论年龄、吸烟史、偏瘫时间、D-二聚体水平、患肢肌力均与脑卒中偏瘫患者发生下肢DVT密切相关,临床中应该对存在上述危险因素的脑卒中偏瘫患者给予重点观察,并给予积极的预防性治疗,以降低脑卒中偏瘫患者发生下肢DVT的风险。

关键词：脑卒中偏瘫下肢深静脉血栓危险因素

氧化应激对hKCFs抗氧化酶、炎性因子和基质重塑相关蛋白基因表达的影响

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太原理工大学学报 2021年第3期52卷 502-508页

作者：宋一菲李晓娜王思佳贺瑞杨继忠吴婷婷太原理工大学生物医学工程学院太原030024 山西省眼科医院准分子激光室太原030002 山西省眼科医院角膜病科太原030002 山西医科大学附属晋中医院口腔科山西晋中030600

通过研究过氧化氢对圆锥角膜成纤维细胞抗氧化能力、炎性因子及基质重塑相关基因表达的影响,探讨氧化应激在圆锥角膜发生与发展过程中的作用。对体外培养的圆锥角膜患者角膜成纤维细胞添加浓度为100μmol/L过氧化氢处理4 h.采用实时荧... 详细信息

通过研究过氧化氢对圆锥角膜成纤维细胞抗氧化能力、炎性因子及基质重塑相关基因表达的影响,探讨氧化应激在圆锥角膜发生与发展过程中的作用。对体外培养的圆锥角膜患者角膜成纤维细胞添加浓度为100μmol/L过氧化氢处理4 h.采用实时荧光定量PCR检测抗氧化酶、炎性因子、基质金属蛋白酶(MMPs)及其抑制剂(TIMPs)和Ⅰ型胶原蛋白(CollagenⅠ)、赖氨酰氧化酶样蛋白(LOXLs)基因表达。结果发现:过氧化氢使抗氧化酶基因(SOD-2、HO-1、NQO-1)、炎性因子(ICAM-1、IL-1β/-6/-8)、MMP-1/-3表达显著上调,CollagenⅠ-α2、TIMP-1/-2/-3、LOXL-1/-3/-4显著下调。结果提示氧化应激可促进圆锥角膜成纤维细胞释放更多的炎性因子,MMPs和TIMPs表达失衡,胶原蛋白降解或交联障碍,引起角膜基质变薄,促进圆锥角膜病变的发生与发展。

关键词：圆锥角膜角膜成纤维细胞氧化应激炎性因子角膜基质重塑相关蛋白

MicroRNA target prediction based on second-order Hidden Markov Model

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Frontiers in Biology 2010年第2期5卷 171-179页

作者： song GAO Liangsheng ZHANG Diangang QIN Tienan FENG yifei WANG Department of Mathematics School of SciencesShanghai UniversityShanghai 200444China School of Life Sciences Institute of Plant BiologyFudan UniversityShanghai 200433China

MicroRNAs are one class of small singlestranded RNA of about 22 nt serving as important negative gene *** animals,miRNAs mainly repress protein translation by binding itself to the 3'UTR regions of mRNAs with imperfect complementary *** bioinformatics investigations have resulted in a number of target prediction tools,all of these have a common shortcoming—a high false positive ***,it is important to further filter the predicted *** this paper,based on miRNA:target duplex,we construct a second-order Hidden Markov Model,implement Baum-Welch training algorithm and apply this model to further process predicted *** model trains the classifier by 244 positive and 49 negative miRNA:target interaction pairs and achieves a sensitivity of 72.54%,specificity of 55.10%and accuracy of 69.62%by 10-fold crossvalidation *** order to further verify the applicability of the algorithm,previously collected datasets,including 195 positive and 38 negative,are chosen to test it,with consistent *** believe that our method will provide some guidance for experimental biologists,especially in choosing miRNA targets for validation.

关键词： microRNA target gene experimentally supported targets second-order Hidden Markov Model forward algorithm

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蓝莓挑振复合采摘技术装置设计与试验

中国农机化学报 2024年第1期45卷 103-108页

作者：李远梅松石志刚蒋清海童一飞南京理工大学机械工程学院南京市210094 农业农村部南京农业机械化研究所南京市210014 宁夏农林科学院枸杞工程技术研究所银川市750002

为解决蓝莓机械化高质量采摘难题,提出一种兼顾回转运动的曲柄滑块机构复合运动挑振方法。通过构建挑振复合运动模型,获取挑振最佳作业参数,结合挑振关键部件胶棒的长度与挠度设计分析,运用MATLAB软件仿真出端点运动过程中满足脱果加速... 详细信息

为解决蓝莓机械化高质量采摘难题,提出一种兼顾回转运动的曲柄滑块机构复合运动挑振方法。通过构建挑振复合运动模型,获取挑振最佳作业参数,结合挑振关键部件胶棒的长度与挠度设计分析,运用MATLAB软件仿真出端点运动过程中满足脱果加速度变化曲线。利用跨行平台集成关键部件,以兔眼蓝莓为采收对象,开展验证试验。试验表明,当胶棒长325 mm、胶棒横截面直径10 mm、自转电机额定转速为40 r/min、往复振动电机额定转速为380 r/min时,成熟蓝莓的采净率可达87.11%,损伤率在6.54%以内,满足相关采收机械的采摘指标,对研究蓝莓高效低耗采收具有一定的指导意义。

关键词：蓝莓机械化采摘挑振复合运动 MATLAB仿真收获机械

Discharge and jet characteristics of gliding arc plasma igniter driven by pressure difference

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Plasma Science and Technology 2022年第11期24卷 93-105页

作者： Xinyao CHENG Huimin song Shengfang HUANG yifei ZHU Zhibo ZHANG Zhenyang LI Min JIA Science and Technology on Plasma Dynamics Laboratory Air Force Engineering UniversityXi’an 710038People’s Republic of China China Aerodynamics Research and Development Center Mianyang 621000People’s Republic of China Institute of Aeroengine Xi’an Jiaotong UniversityXi’an 710049People’s Republic of China

Stable combustion in an afterburner can help increase the thrust of the engine in a short time,thereby improving the maneuverability of a *** improve the ignition performance of an afterburner,a twin-duct ignition platform was designed to study the performance of a gliding arc plasma igniter in close-to-real afterburner *** research was carried out by a combination of experiments and *** working environment of the igniter was explored through a numerical *** results showed that the airflow ejected from the radiating holes formed a swirling sheath,which increased the anti-interference ability of the airflow *** influence of the pressure difference between the inlet and outlet of the igniter(Δp),the flow rate outside the igniter outlet(W_(2)),and the installation angle(α)on the singlecycle discharge energy(E)as well as the maximum arc length(L)were studied through *** stages were identified:the airflow breakdown stage,the arc evolution stage,and the arc fracture stage.E and L increased by 107.3%and 366.2%,respectively,withΔp increasing from 10 to 70 *** relationship between L andΔp obtained by data fitting is L=3-2.47/(1+(Δp/25)^(4)).The relationship of L at differentαis L_(α=0°)>(L_(α=45°)and L_(α=135°))>L_(α=180°)>L_(α=90°).E and L decrease by 18.2%and 37.3%,respectively,whenΔp=45 Torr and W_(2) is increased from 0 to 250 l min^(-1).

关键词： plasma ignition gliding arc

机场跑道混凝土摊铺车辆环境感知与轨迹规划系统设计

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现代机械 2024年第5期 7-13页

作者：吴霄峰张逸飞宋雅楠卓海清熊树生浙江大学福州海卓马克机电设备有限公司

在机场混凝土道面无人化施工的工程背景下，针对道面摊铺与后处理车辆所涉及关键技术进行研究，设计了一种基于多模态传感器的环境感知和轨迹规划系统。通过激光雷达和可见光相机，对采集到的混凝土道面边界信息进行处理和计算，最终规... 详细信息

在机场混凝土道面无人化施工的工程背景下，针对道面摊铺与后处理车辆所涉及关键技术进行研究，设计了一种基于多模态传感器的环境感知和轨迹规划系统。通过激光雷达和可见光相机，对采集到的混凝土道面边界信息进行处理和计算，最终规划出可引导摊铺机行驶的参考轨迹。环境感知模块采用了基于深度学习的图像检测技术和基于点云的特征提取手段，采用卡尔曼滤波算法进行多传感器数据融合；轨迹规划模块通过最小化冲击度的5次多项式差值法进行轨迹规划。实验结果表明，该系统能够实现对道面边界的准确提取，并规划出一条无碰撞且动力学可行的参考轨迹，能够满足车辆行驶与施工的需要，具有一定的应用价值与工程意义。

关键词：履带式车辆环境感知传感器融合轨迹规划