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DEM investigation on conveying of non-spherical particles in a screw conveyor

Particuology 2022年第6期20卷 17-31页

作者： hongyuan sun Huaqing Ma Yongzhi Zhao Institute of Process Equipment College of Energy EngineeringZhejiang UniversityHangzhou 310027China

Screw conveyors are extensively used in modern industry such as metallurgy,architecture and pharmaceutical due to their high-efficiency in the transportation of granular materials.And substantial efforts have been devoted to the study of the screw conveyors.Numerical method is an effective way to study screw conveyor.However,previous studies have mainly focused in the regime of spherical particles while the in-depth investigations for non-spherical particles that should be the most encountered in practical applications are still limited.In view of the above situations,discrete element method(DEM),which has been widely accepted in simulating the discrete systems,is utilized to investigate the conveying process of non-spherical particles in a horizontal screw conveyor,with particles being modeled by super-ellipsoids.In addition,a wear model called SIEM(Shear Impact Energy Model)is incorporated into DEM to predict the wear of screw conveyor.The DEM simulation results demonstrate that the particle shape is influential for the flow behaviors of particles and the wear of conveyor.The conveying performance evaluated quantitatively of both mass flow rate and power consumption is subsequently obtained to investigate the effect of sphericity of particle with different operation parameters.Moreover,particle collision frequency and collision energy consumption are acquired to investigate the possible particle breakage between particles and screw blade.The comparisons between particle-particle collision and particle-wall collision reveal that particles with large shape index have more possibility to be damaged in particle-wall impingement.

关键词： DEM Screw conveyor Super-ellipsoid particle Non-spherical particle Wear

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Symptoms associated with nucleic acid turning-negative-time in COVID-19 patients?

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Acupuncture and Herbal Medicine 2022年第3期2卷 207-209页

作者： Qiang Li Lei Zhang Limin Feng hongyuan sun Yan Ma Xiaoya Liu Cunzhong Shi Mingchi Luo Second Teaching Hospital of Tianjin University of Traditional Chinese Medicine TianjinChina Tianjin Hospital TianjinChina The First Hospital Affiliated to Tianjin University of Traditional Chinese Medicine TianjinChina

Objective:To explore on the association between nucleic acid turning-negative-time and traditional Chinese medicine(TCM)symptoms in coronavirus disease 2019(COVID-19)patients with the Omicron variant.Method:For this retrospective cross-sectional study,we enrolled 189 patients with COVID-19(age 20-90 years)were included.multiple linear regression models were used to investigate the TCM symptoms affecting the nucleic acid turning-negative-time of COVID-19 patients,during the process of data analysis,taking with nucleic acid turning-negative-time as the dependent variable,and TCM symptoms as independent variables,and at the same time,sex,age,hypertension,diabetes,and coronary heart disease were as confounding variables.Results:The study found that the most common TCM symptoms of COVID-19 patients with Omicron were cough,dry throat,expectoration,fever,sore throat,pharyngeal itching,running nose,and nasal congestion.Regression analysis showed that the fit regressive equation showed a significant difference(F=4.286,P<0.001),R=0.400,the adjusted R^(2)=0.123,and three variables in the regression equation showed significant difference(P<0.05).The results showed that nucleic acid turningnegative-time was mostly related to constipation,fever,and expectoration.If the patients had the symptoms of constipation,fever,and expectoration;that is,if patients showed these symptoms,the turning-negative-time of nucleic acid in patients with Omicron will be prolonged.Conclusions:Treatment based on symptoms for patients with constipation,fever,and expectoration may have important clinical significance for the COVID-19 patients with Omicron.

关键词： COVID-19 Omicron TCM symptoms nucleic acid turning-negative-time

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风景资源保育政策对游客及原住民行为意向影响研究——以神农架国家公园为例

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干旱区资源与环境 2024年第2期38卷 181-189页

作者：刘思源孙彦斐韩鸿远南京工业大学艺术设计学院南京211816 南京信息工程大学艺术学院南京210044

文中以神农架国家公园风景资源为研究载体,以计划行为理论为基础,基于296份有效问卷,将保育政策作为调节变量,建立了国家公园风景资源“保育行为意向”与“保育政策”相互关系的研究框架,通过二阶结构方程模型,揭示了国家公园风景资源... 详细信息

文中以神农架国家公园风景资源为研究载体,以计划行为理论为基础,基于296份有效问卷,将保育政策作为调节变量,建立了国家公园风景资源“保育行为意向”与“保育政策”相互关系的研究框架,通过二阶结构方程模型,揭示了国家公园风景资源保育行为意向与保育政策的内在关系。研究结果表明:保育政策对保育行为、社会规范、保育行为态度、感知行为控制的标准化路径系数分别为0.680、0.760、0.65,保育政策对利益群体的保育行为具有显著的正向影响。基于研究结论提出政策启示:1)加强风景资源生态管理与宣传教育,提升原住民及游客的保育意识,开展环境教育规范保育行为。2)保育政策需以人的福祉为依归,提倡公益性。3)平衡人与风景资源的关系,推进资源可持续发展。

关键词：风景资源保育政策行为意向 SEM 神农架

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椎管内穿刺置管后诱发马尾神经综合征诊断室管膜瘤1例

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中华麻醉学杂志 2024年第5期44卷 629-630页

作者：孙莹张洪远李普乐陶宏滕州市中心人民医院麻醉科滕州277500

患者,女性,年龄45岁,身高155 cm,体质量57 kg。因"大便时肛门处肿物脱出,便后不能还纳"入院。既往甲状腺功能减退病史7年,口服左甲状腺素钠片治疗,病情控制良好;剖腹产手术史20余年,自诉曾因腰部疼痛行腰部牵引治疗,近十来年无明显腰腿... 详细信息

患者,女性,年龄45岁,身高155 cm,体质量57 kg。因"大便时肛门处肿物脱出,便后不能还纳"入院。既往甲状腺功能减退病史7年,口服左甲状腺素钠片治疗,病情控制良好;剖腹产手术史20余年,自诉曾因腰部疼痛行腰部牵引治疗,近十来年无明显腰腿部不适。诊断为混合痔、便秘、甲状腺功能减退,拟在椎管内阻滞下行吻合器痔上黏膜环切加痔外剥内扎术。ASA分级Ⅱ级,心电图及各项实验室检查未见明显异常。

关键词：腰部疼痛病情控制肿物脱出室管膜瘤甲状腺功能减退混合痔左甲状腺素钠片椎管内阻滞

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基于实际预压载作业的自升式平台环境载荷图谱绘制新思路

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哈尔滨工程大学学报（英文版） 2024年第1期23卷 209-221页

作者：孙承猛林海花张志刚孙洪源周立师 Naval Architecture and Port Engineering College Shandong Jiao Tong UniversityWeihai 264209China School of Ocean Engineering Harbin Institute of TechnologyWeihai 264209China China Merchants Jinling Shipyard(Weihai)Co. Ltd.Weihai 264207China

The environmental load chart is an important technical support required for the jack-up drilling platform to facilitate its adaptation to different operating waters and ensure the safety of operation.This chart is a crucial part of the platform operation manual.The chart data are closely related to external factors such as water depth,wind,wave,and current conditions of the working water,as well as to the structural characteristics of the platform itself and the number of variable loads.This study examines the platform state under extreme wind,wave,and current conditions during preloading.In addition,this study focuses on the difference between the ultimate reaction force of the pile leg during preloading and the reaction force of the pile leg without considering any environmental load before preloading.Furthermore,the relationship between the difference and the new reaction force of the pile leg caused by the combination of different environmental conditions is established to facilitate the construction of a new form of environmental load chart.The newly formed chart is flexible and simple;thus,it can be used to evaluate the environmental adaptability of the platform in the target well location and provides the preloading target demand or variable load limit according to the given environmental constraints.Moreover,the platform can perform personalized preloading operations,thereby improving its capability to cope with complex geological conditions,such as reducing punch-through risks.This condition reduces the load on jacking system devices and increases its service life.

关键词： Jack-up Environmental load chart Preloading Geometrically nonlinear effect Punch through

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锂基脂静态热氧化老化行为的红外吸收光谱定量分析

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石油学报（石油加工） 2024年第2期40卷 560-568页

作者：孙一平赵启龙苏怀刚于泓渊阴俊娄文静中国科学院兰州化学物理研究所固体润滑国家重点实验室甘肃兰州730000 青岛市资源化学与新材料研究中心山东青岛266000

为探讨锂基润滑脂在高温使用工况下的热老化行为,以不同矿物油、合成油PAO为基础油,以12-羟基硬脂酸锂为稠化剂制备润滑脂样品。使用自行设计的红外光谱定量分析设备,采用静态热老化方式模拟并系统研究了不同老化温度、不同基础油种类... 详细信息

为探讨锂基润滑脂在高温使用工况下的热老化行为,以不同矿物油、合成油PAO为基础油,以12-羟基硬脂酸锂为稠化剂制备润滑脂样品。使用自行设计的红外光谱定量分析设备,采用静态热老化方式模拟并系统研究了不同老化温度、不同基础油种类的锂基润滑脂老化过程。探索了该老化过程中的润滑脂中关键组分分子结构变化及其规律,并分析建立了可用于有效评定润滑脂热老化程度的综合性能指标E。结果表明:锂基润滑脂的热老化过程中,首先基础油发生氧化、硝化、硫化等反应,随着老化程度的加剧,稠化剂发生降解;对于140℃下静态热老化的1#锂基脂样品,E值上升至新脂的1~23倍时为初级氧化阶段,上升至23~38倍时为氧化的平台阶段,结合其他理化指标,前2个阶段为影响润滑脂寿命的主要部分,随老化时间增加,E值继续上升,润滑脂结构开始降解失效。另外,润滑脂老化程度随温度的升高而加速。基础油种类对老化速率有一定影响,聚α烯烃规整的长链烷烃结构在老化过程后期能够保持稠化剂结构的稳定,制备的润滑脂样品具有更好的高温性能。

关键词：锂基脂热老化红外光谱定量分析基础油

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钛合金与碳纤维复合身管在无后坐力炮中的应用分析

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火炮发射与控制学报 2024年第1期45卷 62-67页

作者：孙向东谢鑫戴泓源王佳闫旭冯茂林河北燕兴机械有限公司河北张家口075000

为满足现代装备轻量化要求,以无后坐力炮的钛合金与碳纤维复合身管为研究对象,采用静态水压试验方法测得变形率,分别与理论计算、数值模拟计算的变形率进行符合性验证,得到实测变形率与理论计算变形率误差在±5%以内,实测变形率与模拟... 详细信息

为满足现代装备轻量化要求,以无后坐力炮的钛合金与碳纤维复合身管为研究对象,采用静态水压试验方法测得变形率,分别与理论计算、数值模拟计算的变形率进行符合性验证,得到实测变形率与理论计算变形率误差在±5%以内,实测变形率与模拟计算变形率误差在±6%以内,变形率误差在可接受范围。对碳纤维复合材料身管进行水压爆破试验,结果表明:碳纤维T700和M46的安全应力和变形率分别为1.874 4 GPa、1.18%和1.465 9 GPa、0.6%,在该试验数据的基础上,使用实炮进行射击试验,测得的最大变形率为0.19%,该变形率小于0.6%,从工程应用角度考虑,钛合金内衬外缠碳纤维复合材料能够满足身管轻量化应用要求。

关键词：无后坐力炮钛合金碳纤维仿真应变弹性模量

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Diffusion Analysis and Modeling of Potassium Sorbate in Gelatin Based Antimicrobial Film

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Journal of Materials Science and Chemical Engineering 2016年第7期4卷 1-7页

作者： Hui Wang Jieyu He hongyuan sun Department of Food Science and Technology Hainan Tropic Ocean University Sanya China

The diffusion of potassium sorbate incorporated into gelatin based antimicrobial film was measured. Fick’s second law was applied to investigate the mechanism of potassium sorbate released from the films. The mathematical model was established. The result showed that the diffusion coefficient D increased with the increase of potassium sorbate concentration. The effects of temperature 5?C, 25?C and 35?C on diffusion were investigated. The mechanisms of potassium sorbate diffusion through gelatin films were mainly Fickian and determined by the power law model Mt/M∞ = k × tn. A decrease in temperature from 35?C to 5?C resulted in a reduction of diffusion coefficients from 5.20 × 10?12 to 1.36 × 10?12 m2/s. The diffusion coefficient of potassium sorbate is influenced by receiving solution pH values.

关键词： Potassium Sorbate Gelatin Diffusivity Fick’s Mathematical Model

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A precision-drive hysteresis model with an equal-density weight function for GMA feedforward compensation

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Nanotechnology and Precision Engineering 2023年第2期6卷 13-24页

作者： Kun Xiao Zhiwen Wang hongyuan Wang Jie sun Yelong Zheng Yinguo Huang State Key Laboratory of Precision Measuring Technology and Instruments Tianjin UniversityTianjin 300072China

Giant magnetostrictive actuators(GMAs) are a widely used type of micro-nano actuator, and they are greatly significant in the field of precision engineering. The accuracy of a GMA often depends on its hysteresis model. However, existing models have some limitations,including the difficulty of identifying their parameters and the tradeoff between the quantity of modeling data required and the level of precision achieved. To solve these problems, in this paper, we propose a Preisach inverse model based on equal-density segmentation of the weight function(E-Preisach). The weight function used to calculate the displacement is first discretized. Then, to obtain a finer weight distribution, the discretized geometric units are uniformly divided by area. This can further minimize the output displacement span, and it produces a higher-precision hysteresis model. The process of parameter identification is made easier by this approach, which also resolves the difficulty of obtaining high precision using a small amount of modeling data. The Preisach and the E-Preisach inverse models were investigated and compared using experiments. At frequencies of 1 and 5 Hz, it was found that the E-Preisach inverse model decreases the maximum error of the feedforward compensation open-loop control to within 1 μm and decreases the root-mean-square error in displacement to within0.5 μm without the need to increase the number of measured hysteresis loops. As a result, the E-Preisach inverse model streamlines the structure of the model and requires fewer parameters for modeling. This provides a high-precision modeling method using a small amount of modeling data;it will have applications in precision engineering fields such as active vibration damping and ultra-precision machining.

关键词： Micro-nano actuator GMA Hysteresis model Preisach model

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Fabrication of edge-curled petals-like covalent organic frameworks and their properties for extracting indole alkaloids from complex biological samples

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Journal of Pharmaceutical Analysis 2022年第1期12卷 96-103页

作者： Fanrong sun Ligai Bai Mingxue Li Changqing Yu Haiyan Liu Xiaoqiang Qiao hongyuan Yan College of Pharmaceutical Sciences Hebei UniversityBaoding071002HebeiChina Key Laboratory of Medicinal Chemistry and Molecular Diagnosis of Ministry of Education Baoding071002HebeiChina Institute of Life Science and Green Development Hebei UniversityBaoding071002HebeiChina

In this study,a functionalized covalent-organic framework(COF)was first synthesized using porphyrin as the fabrication unit and showed an edge-curled,petal-like and well-ordered structure.The synthesized COF was then introduced to prepare porous organic polymer monolithic materials(POPMs).Two composite POPM/COF monolithic materials with rod shapes,referred to as sorbent A and sorbent B,were prepared in stainless steel tubes using different monomers.Sorbents A and B exhibited relatively uniform porous structures and enhanced specific surface areas of 153.14 m;/g and 80.01 m;/g,respectively.The prepared composite monoliths were used as in-tube solid-phase extraction(SPE)sorbents combined with HPLC for the on-line extraction and quantitative analytical systems.Indole alkaloids(from Catharanthus roseus G.Don and Uncaria rhynchophylla(Miq.)Miq.Ex Havil.)contained in mouse plasma were extracted and quantitatively analyzed using the online system.The two composite multifunctional monoliths showed excellent clean-up ability for complex biological matrices,as well as superior selectivity for target indole alkaloids.Method validation showed that the RSD values of the repeatability(n=6)were≤3.46%,and the accuracy expressed by the spiked recoveries was in the ranges of 99.38%-100.91%and 96.39%-103.50%for vinca alkaloids and Uncaria alkaloids,respectively.Furthermore,sorbents A and B exhibited strong reusability,with RSD values≤5.32%,which were based on the peak area of the corresponding alkaloids with more than 100 injections.These results indicate that the composite POPM/COF rod-shaped monoliths are promising media as SPE sorbents for extracting trace compounds in complex biological samples.

关键词： Covalent organic frameworks Monolithic material Solid-phase extraction Alkaloids Biological samples

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