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Activation mechanism of ammonium oxalate with pyrite in the lime system and its response to flotation separation of pyrite from arsenopyrite

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International Journal of Minerals,Metallurgy and Materials 2023年第2期30卷 271-282页

作者： Runpeng Liao Shuming Wen Qicheng Feng Jiushuai Deng hao lai State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization Faculty of Land Resource EngineeringKunming University of Science and TechnologyKunming 650093China Yunnan Key Laboratory of Green Separation and Enrichment of Strategic Mineral Resources Kunming University of Science and TechnologyKunming650093China School of Chemical&Environmental Engineering China University of Mining&Technology(Beijing)Beijing 100083China Liuzhou China-Tin Nonferrous Design and Research Institute Co. Ltd.China Tin GroupLiuzhou 545006China

The activation properties of ammonium oxalate on the flotation of pyrite and arsenopyrite in the lime system were studied in this work.Single mineral flotation tests showed that the ammonium oxalate strongly activated pyrite in high alkalinity and high Ca^(2+)system,whereas arsenopyrite was almost unaffected.In mineral mixtures tests,the recovery difference between pyrite and arsenopyrite after adding ammonium oxalate is more than 85%.After ammonium oxalate and ethyl xanthate treatment,the hydrophobicity of pyrite increased significantly,and the contact angle increased from 66.62°to 75.15°and then to 81.21°.After ammonium oxalate treatment,the amount of ethyl xanthate adsorption on the pyrite surface significantly increased and was much greater than that on the arsenopyrite surface.Zeta potential measurements showed that after activation by ammonium oxalate,there was a shift in the zeta potential of pyrite to more negative values by adding xanthate.X-ray photoelectron spectroscopy test showed that after ammonium oxalate treatment,the O 1s content on the surface of pyrite decreased from 44.03%to 26.18%,and the S 2p content increased from 14.01%to 27.26%,which confirmed that the ammonium oxalatetreated pyrite surface was more hydrophobic than the untreated surface.Therefore,ammonium oxalate may be used as a selective activator of pyrite in the lime system,which achieves an efficient flotation separation of S-As sulfide ores under high alkalinity and high Ca2+concentration conditions.

关键词： pyrite arsenopyrite ammonium oxalate flotation separation

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Effectiveness of cardioneuroablation in different subtypes of vasovagal syncope

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Journal of Geriatric Cardiology 2024年第6期21卷 651-657页

作者： Bin TU Zi-hao lai Ai-Yue CHEN Zhi-Yuan WENG Si-Min CAI Zhu-Xin ZHANG Li-Kun ZHOU Li-Hui ZHENG Yan YAO Arrhythmia Center Fuwai HospitalNational Center for Cardiovascular DiseasesNational Key LaboratoryChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Cardiac Center Beijing Chaoyang HospitalCapital Medical UniversityBeijingChina Cardiovascular Department The First Affiliated HospitalFujian Medical UniversityFujian Institute of HypertensionFujianChina Department of Cardiovascular The Second Affiliated Hospital of Zhejiang University School of MedicineZhejiangChina

BACKGROUND Cardioneuroablation(CNA)has shown encouraging results in patients with vasovagal syncope(VVS).However,data on different subtypes was scarce.METHODS This observational study retrospectively enrolled 141 patients[mean age:40±18 years,51 males(36.2%)]with the diagnosis of VVS.The characteristics among different types of VVS and the outcomes after CNA were analyzed.RESULTS After a mean follow-up of 4.3±1.5 years,41 patients(29.1%)experienced syncope/pre-syncope events after CNA.Syncope/pre-syncope recurrence significantly differed in each subtype(P=0.04).The cardioinhibitory type of VVS had the lowest recurrence rate after the procedure(n=6,16.7%),followed by mixed(n=26,30.6%)and vasodepressive(n=9,45.0%).Additionally,a significant difference was observed in the analyses of the Kaplan-Meier survival curve(P=0.02).Syncope/pre-syncope burden was significantly reduced after CNA in the vasodepressive type(P<0.01).Vasodepressive types with recurrent syncope/pre-syncope after CNA have a lower baseline deceleration capacity(DC)level than those without(7.4±1.0 ms vs.9.0±1.6 ms,P=0.01).Patients with DC<8.4 ms had an 8.1(HR=8.1,95%CI:2.2-30.0,P=0.02)times risk of syncope/pre-syncope recurrence after CNA compared to patients with DC≥8.4 ms,and this association still existed after adjusting for age and sex(HR=8.1,95%CI:2.2-30.1,P=0.02).CONCLUSIONS Different subtypes exhibit different event-free rates.The vasodepressive type exhibited the lowest event-free rate,but those patients with DC≥8.4 ms might benefit from CNA.

关键词： syncope subtypes diagnosis

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Influence of particle size and ionic strength on the freeze-thaw stability of emulsions stabilized by whey protein isolate

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Food Science and Human Wellness 2022年第4期11卷 922-932页

作者： hao lai Fuchao Zhan Yujie Wei Abel W.S.Zongo Sha Jiang haomin Sui Bin Li Jing Li College of Food Science and Technology Huazhong Agricultural UniversityWuhan 430070China Key Laboratory of Environment Correlative Dietology(Huazhong Agricultural University) Ministry of EducationWuhan 430070China

The influence of particle size and ionic strength on the freeze-thaw(FT) stability of emulsions stabilized by whey protein isolate(WPI) was investigated in this study. The destabilization of emulsions during the FT process could be suppressed in a way by decreasing the particle size of the initial emulsions, which was the result of retarding the coalescence between oil droplets. To further improve the FT stability of emulsions, different amounts of Na Cl were added before emulsification. The emulsions with the ionic strength at 30–50 mmol/L exhibited good FT stability. Notably, the ionic strength in this range would not lower the freezing point of emulsions below the freezing temperature used in this study. Salt addition could improve the structural properties of proteins, which was available to strengthen the rigidity and thickness of interfacial layers, sequentially building up the resistance that the destruction of ice crystals to emulsions. Moreover, stronger flocculation between emulsion droplets could promote the formation of a gel-like network structure dominated by elasticity in the emulsion system, which might effectively inhibit the movement of droplets, and improve the FT stability of emulsions eventually. The result was of great significance for the preparation of emulsion-based foods with improved FT stability.

关键词： Emulsion Freeze-thaw stability Whey protein isolate Particle size Ionic strength

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尿素包合法提纯亚麻籽油中α-亚麻酸工艺的优化研究

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化学工程师 2024年第2期38卷 87-91页

作者：郝文来郝健深圳市诚致生物开发有限公司广东深圳518000

本文以亚麻籽油为原料油,α-亚麻酸为提取目标产物,采用单因素法研究了不同尿素溶液与脂肪酸体积比、包合温度、包合时间以及尿素-乙醇溶液浓度等对α-亚麻酸提取率的影响,优化了α-亚麻酸的提取工艺。实验结果表明,当脂肪酸与尿素溶液... 详细信息

本文以亚麻籽油为原料油,α-亚麻酸为提取目标产物,采用单因素法研究了不同尿素溶液与脂肪酸体积比、包合温度、包合时间以及尿素-乙醇溶液浓度等对α-亚麻酸提取率的影响,优化了α-亚麻酸的提取工艺。实验结果表明,当脂肪酸与尿素溶液体积比为1∶45、尿素-乙醇溶液浓度为1mol·L^(-1)、包合温度为-15℃、包合时间为24h时,α-亚麻酸提取率可达81%。并通过液相色谱对提纯的α-亚麻酸进行表征,α-亚麻酸在12.5min出峰,符合α-亚麻酸的出峰位置。

关键词：亚麻籽油 α-亚麻酸尿素包合法提纯

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基于离散元的重载铁路有砟轨道阻力特性研究

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铁道工程学报 2024年第3期41卷 23-28,37页

作者：刘文硕夏栋文赖豪曾志平吕方舟中南大学长沙410075 中机国际工程设计研究院有限责任公司长沙410021

研究目的:有砟轨道在重载铁路中广泛采用,随着服役时间的增加,在列车荷载反复作用下,道床性能会随之变化,线路阻力呈现动态发展的时变特性。作为求解梁轨相互作用的关键,准确合理地选取线路纵向阻力是保证梁轨相互作用计算准确的前提,... 详细信息

研究目的:有砟轨道在重载铁路中广泛采用,随着服役时间的增加,在列车荷载反复作用下,道床性能会随之变化,线路阻力呈现动态发展的时变特性。作为求解梁轨相互作用的关键,准确合理地选取线路纵向阻力是保证梁轨相互作用计算准确的前提,关系梁轨系统的正常使用与安全运营。研究结论:(1)颗粒级配由粗到细,纵向线阻力逐渐减小;摩擦系数由小到大,纵向线阻力稍微增加;(2)结合不同级配建立的道床模型模拟出的纵向线阻力-位移曲线,获得纵向线阻力动态演化模型,可知线路纵向阻力由新建线路的阻力29.7 kN/(m·线)演化到破碎充分时的23.6 kN/(m·线),退化幅度约为20.5%;(3)本研究成果可为开展全服役期内重载铁路的梁轨相互作用等相关研究提供关键参数。

关键词：线路阻力有砟轨道离散元法道砟级配时变特性

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Frost heave analysis of ballasted track above box culvert and its influence on train vibration

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Research in Cold and Arid Regions 2017年第3期9卷 229-235页

作者： Bin Luo hao lai Tatsuya Ishikawa Tetsuya Tokoro Graduate School of Engineering Hokkaido University Faculty of Engineering Hokkaido University National Institute of Technology Tomakomai College

The uneven frost heave of frost-susceptible subgrade soil causes track irregularity,which highly enhances train vibration and affects the comfort and safety of railway transportation.This paper presents a coupled thermo-hydro-mechanical(THM)analysis for the freezing behavior of railway located above a box culvert.The vertical acceleration of the vehicle,an indicator of riding comfort,is predicted through a vehicle dynamic model.The results reveal that the existence of a box culvert changes the subgrade thermal pattern,leading to a deeper frost penetration depth.The frost heave amount above the box culvert is larger than the adjacent section,resulting in uneven track structure upheave and track irregularity.This frostinduced track irregularity highly affects train vibration.

关键词： railway box culvert coupled analysis uneven frost heave track irregularity train vibration

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Ultrasound-guided stellate ganglion blockade: an appealing tactic for cardiac electrical storm

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Journal of Geriatric Cardiology 2023年第5期20卷 376-382页

作者： Zi-hao lai Li-Hui ZHENG Yan YAO Arrhythmia Center Fuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina

Ventricular arrhythmia(VA)is a life-threatening cardiac emergency.When VA occurs three times or more within 24 h and interventions are required,it is defined as an electrical storm(ES)characterized by refractoriness and recurrence.[1]For patients with implantable cardioverter defibrillator(ICD),the notion is redefined as no fewer than three appropriate and separate(at least 5 min for each interval)ICD interventions given within 24 h.

关键词： cardiac storm electrical

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光流法修正的时序图像语义分割模型

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计算机工程与科学 2024年第1期46卷 102-110页

作者：邱晓梦王琳谷文俊宋伟田浩来胡誉郑州大学河南省大数据研究院河南郑州450052 郑州大学计算机与人工智能学院河南郑州450001 北京唯迈医疗设备有限公司北京100000 中国科学院高能物理研究所北京100049

医学成像技术的发展带来了海量的医学图像数据,这些图像反映了生物体的内部结构特征,医学图像分割技术可以提高医疗人员的诊断效率,从而成为现代医疗诊断的重要辅助手段之一。然而成像过程中不可避免地会出现噪声或伪影,它们给分割工作... 详细信息

医学成像技术的发展带来了海量的医学图像数据,这些图像反映了生物体的内部结构特征,医学图像分割技术可以提高医疗人员的诊断效率,从而成为现代医疗诊断的重要辅助手段之一。然而成像过程中不可避免地会出现噪声或伪影,它们给分割工作带来了极大的挑战。现有的分割模型中,单帧医学图像语义分割模型未考虑图像帧与帧之间的关系,视频语义分割模型虽利用了时序信息,但在边缘提取上有所欠缺。为了解决以上问题,提出了一种以U-Net为骨干,用光流法进行修正的时序语义分割模型。该模型能够提取视频前后帧之间的光流信息,并对当前帧与光流进行特征提取与权重分配,以达到修正的效果。实验结果表明,在果蝇电镜图、腹部综合器官图和冠状动脉造影图这些不同类型的数据集上,该模型在相似性系数、像素准确率和交并比这3个评价指标上都获得了最优结果,验证了所提模型的有效性和泛化性。

关键词： U-Net 光流医学图像语义分割深度学习

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寒区沥青混合料阻裂性能研究进展

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应用化工 2024年第2期53卷 458-462页

作者：毛楠翟健梁赖淏师长春陆福洋熊锐长安大学材料科学与工程学院陕西西安710061

从材料研究与路面结构设计等角度综述了沥青及沥青混合料的低温性能研究进展,以沥青低温性能评价、沥青混合料低温性能评价及混合料低温性能仿真模拟评价三个角度介绍了近年来国内外针对沥青及沥青混合料的低温性能评价研究。认为应在... 详细信息

从材料研究与路面结构设计等角度综述了沥青及沥青混合料的低温性能研究进展,以沥青低温性能评价、沥青混合料低温性能评价及混合料低温性能仿真模拟评价三个角度介绍了近年来国内外针对沥青及沥青混合料的低温性能评价研究。认为应在材料研究、路面设计的基础上对高寒、大温差地区的路面低温性能展开探索;建立同高寒、大温差气候条件相适应的耐久性路面低温性能评价指标;并同时从力学仿真模拟领域入手,对沥青混合料的抗裂力学性能变化趋势进行深入研究。

关键词：寒区道路工程沥青混合料低温抗裂评价指标

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脉冲磁场对稀土AZ91D镁合金凝固组织及性能的影响

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铸造 2024年第1期73卷 68-75页

作者：来昊民白庆伟田迎春许鹏梁忠刘昕旸内蒙古科技大学材料与冶金学院内蒙古包头014010 内蒙金属材料研究所内蒙古包头014034

研究了脉冲磁场对稀土AZ91D镁合金凝固组织及力学性能的影响。研究表明:在AZ91D镁合金中加入适量稀土La有利于晶粒细化,形成新的稀土针状化合物Al_(2)La;在AZ91D-0.75La合金凝固过程中施加脉冲磁场处理后,针状化合物Al_(2)La长度更加短... 详细信息

研究了脉冲磁场对稀土AZ91D镁合金凝固组织及力学性能的影响。研究表明:在AZ91D镁合金中加入适量稀土La有利于晶粒细化,形成新的稀土针状化合物Al_(2)La;在AZ91D-0.75La合金凝固过程中施加脉冲磁场处理后,针状化合物Al_(2)La长度更加短小,甚至趋于球化;同时,AZ91D-0.75La合金的凝固组织和力学性能得到进一步改善,当脉冲占空比为20%、频率为20 Hz时,合金的处理效果最好,晶粒尺寸从156.3μm下降至103.5μm,细化了33.78%,维氏硬度也从HV 53.8增加至HV 69.4。

关键词：稀土镁合金脉冲磁场凝固组织析出相

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