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纳米流体的制备、稳定性及热物性研究进展

材料导报 2024年第4期38卷 229-239页

作者：江巍雪汤新宇宋金蔚徐祚张源扬州大学电气与能源动力工程学院江苏扬州225100 西部绿色建筑国家重点实验室西安710055

作为一类新型固液两相流体,纳米流体相比于基础流体,其导热系数、表面张力等热物性的优势已逐渐被认可。然而,纳米颗粒的高表面活性以及颗粒间的高吸引力使纳米颗粒极易团聚并沉淀,导致纳米流体的热物性优势被削弱,进而影响传热效果。因... 详细信息

作为一类新型固液两相流体,纳米流体相比于基础流体,其导热系数、表面张力等热物性的优势已逐渐被认可。然而,纳米颗粒的高表面活性以及颗粒间的高吸引力使纳米颗粒极易团聚并沉淀,导致纳米流体的热物性优势被削弱,进而影响传热效果。因此,制备既具优良热物性又具较强稳定性的纳米流体成为将其规模化应用的前提。为此,本文对纳米流体的制备、稳定性与热物性进行了总结分析,归纳了通过磁力搅拌、调节基液pH、超声分散技术、颗粒表面改性技术及添加表面活性剂以促进颗粒的稳定分散的技术特点。通过分析各类参数对纳米流体热物性的影响,指出解决颗粒团聚与沉淀问题的有效研究方向,以期满足纳米流体实际应用的需求。

关键词：纳米流体制备稳定性团聚与沉淀热物性

工程机械智能制造专业群生产性实践教学体系构建研究

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湖北开放职业学院学报 2024年第13期37卷 170-171,177页

作者：徐作栋天津职业技术师范大学天津300222 湖南三一工业职业技术学院湖南长沙410129

随着职业教育改革的深入,职业院校越来越重视实践教学。实践教学应面向市场,关注行业企业的发展需求,从传统的专业导向向产业导向转变,实现学生学习的技术技能从滞后适应产业变革向与产业同步发展转变,从而构建工学结合的实践育人机制... 详细信息

随着职业教育改革的深入,职业院校越来越重视实践教学。实践教学应面向市场,关注行业企业的发展需求,从传统的专业导向向产业导向转变,实现学生学习的技术技能从滞后适应产业变革向与产业同步发展转变,从而构建工学结合的实践育人机制。以高职院校工程机械智能制造专业群为例构建了生产性实践教学体系,包括目标体系、内容与方法体系、资源体系。构建的目标体系以面向行业企业为出发点,构建的内容体系还原了真实的职业情境,构建的资源体系保障了生产性实践教学的顺利实施。通过这套体系培养的学生学习的目标性更明确,人才培养针对性更强,真正地实现了专业实践学习与企业工作岗位的有机衔接,学生综合能力和实际工作能力都得到了显著的提高。

关键词：专业群生产性实践教学体系

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益生菌发酵谷物饮料研究进展

农产品加工 2024年第15期 100-104,107页

作者：左旭吴兴壮沈阳农业大学辽宁沈阳110866 辽宁省农业科学院食品与加工研究所辽宁沈阳110161

近年来,以五谷杂粮为主要原料,经益生菌发酵且具有独特的营养功效和风味的谷物饮料受到消费者的青睐。通过阐述益生菌及其发酵谷物高营养、促健康的功能特性,以及益生菌发酵谷物饮料的部分原材料高营养的特性,综述了益生菌发酵谷物饮料... 详细信息

近年来,以五谷杂粮为主要原料,经益生菌发酵且具有独特的营养功效和风味的谷物饮料受到消费者的青睐。通过阐述益生菌及其发酵谷物高营养、促健康的功能特性,以及益生菌发酵谷物饮料的部分原材料高营养的特性,综述了益生菌发酵谷物饮料的加工工艺流程,对益生菌发酵谷物饮料未来发展方向进行展望,为今后益生菌发酵型谷物饮料的研究提供参考。

关键词：谷物饮料益生菌发酵

Long-term prediction for hierarchical-B-picture-based coding of video with repeated shots

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Frontiers of Information Technology & Electronic Engineering 2018年第3期19卷 459-470页

作者： xu-guang zuo Lu YU Zhejiang Provincial Key Laboratory of Information Processing Communication and Networking IPCANInstitute of Information and Communication Engineering Zhejiang University

The latest video coding standard High Efficiency Video Coding （HEVC） can achieve much higher coding efficiency than previous video coding standards. Particularly, by exploiting the hierarchical B-picture prediction structure, temporal redundancy among neighbor frarnes is eliminated remarkably well. In practice, videos available to consumers usually contain many repeated shots, such as TV series, movies, and talk shows. According to our observations, when these videos are encoded by HEVC with the hierarchical B-picture structure, the temporal correlation in each shot is well exploited. However, the long-term correlation between repeated shots has not been used. We propose a long-term prediction （LTP） scheme to use the long-term temporal correlation between correlated shots in a video. The long-term reference （LTR） frames of a source video are chosen by clustering similar shots and extracting the representative frames, and a modified hierarchical B-picture coding structure based on an LTR frame is introduced to support long-term temporal prediction. An adaptive quantization method is further designed for LTR frames to improve the overall video coding efficiency. Experimental results show that up to 22.86% coding gain can be achieved using the new coding scheme.

关键词： High Efficiency Video Coding(HEVC) Long-term temporal correlation Long-term prediction Hierarchical B-picture structure

Enhancing ferromagnetic coupling in CrXY(X=O,S,Se;Y=Cl,Br,I)monolayers by turning the covalent character of Cr-X bonds

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npj Computational Materials 2023年第1期9卷 1781-1786页

作者： Hao-Ran Zhu Bin Shao xu zuo College of Electronic Information and Optical Engineering Nankai UniversityTianjinChina Tianjin Key Laboratory of Optoelectronic Sensor and Sensing Network Technology Nankai UniversityTianjinChina Key Laboratory of Photoelectronic Thin Film Devices and Technology of Tianjin Nankai UniversityTianjinChina Engineering Research Center of Thin Film Optoelectronics Technology Ministry of EducationNankai UniversityTianjinChina

On the basis of first-principles calculations,we investigate the electronic and magnetic properties of 1T phase chromium sulfide halide CrXY(X=O,S,Se;Y=Cl,Br,I)monolayers in CrCl_(2) structure with the P3m1 space *** for the CrOI monolayer,all CrXY monolayers are stable and ferromagnetic *** results show that the ferromagnetic coupling is dominated by the kinetic exchange between the empty e_(g)-orbital of Cr atoms and the p-orbital of anions under the three-fold rotational *** this context,the coupling strength allows for being greatly enhanced by turning the nature of Cr–X bonds,i.e.,increasing the covalent contribution of the bonds by minimizing the energy difference of the coupled *** we illustrate for the example of CrOY,the Curie temperature(T_(c))is nearly tripled by substituting O by S/Se ion,eventually reaching the highest Tc in CrSeI monolayer(334 K).The high stabilities and Curie temperature manifest these monolayer ferromagnetic materials feasible for synthesis and applicable to 2D spintronic devices.

关键词： ferromagnetic bonds coupling

基于变载工况的海上风电机组主轴轴承刚柔耦合动态响应分析

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轴承 2024年第9期 52-62页

作者：庞晓旭朱定康左旭郝文路邱明河南科技大学机电工程学院河南洛阳471003 机械装备先进制造河南省协同创新中心河南洛阳471003 高端轴承河南省协同创新中心河南洛阳471003 洛阳新强联回转支承股份有限公司河南洛阳471822

针对海上风电机组主轴用三排圆柱滚子轴承在恒载工况下的仿真结果存在局限性、片面性的问题,提出了一种变载工况下的仿真分析方法,建立了轴承接触力学模型和柔性体模型并对轴承内圈、外圈、保持架进行了刚柔耦合处理。基于变载工况,分... 详细信息

针对海上风电机组主轴用三排圆柱滚子轴承在恒载工况下的仿真结果存在局限性、片面性的问题,提出了一种变载工况下的仿真分析方法,建立了轴承接触力学模型和柔性体模型并对轴承内圈、外圈、保持架进行了刚柔耦合处理。基于变载工况,分析了刚性模型与刚柔耦合模型的理论速度、仿真速度以及加速度响应,并通过刚柔耦合模型研究了三排圆柱滚子轴承内部不同接触表面的接触力特性,结果表明:刚性模型的自转误差比刚柔耦合模型大3.67~22.6倍,刚柔耦合模型的加速度趋势更加平稳且速度波动更小;近风叶轮毂端的推力滚子受力约是远端推力滚子的1.85倍,保持架的平均受力是远端保持架的1.6倍。

关键词：滚动轴承风力发电机组圆柱滚子轴承变载荷刚柔耦合动态响应

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Anomaly IoT Node Detection Based on Local Outlier Factor and Time Series

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Computers, Materials & Continua 2020年第8期64卷 1063-1073页

作者： Fang Wang Zhe Wei xu zuo School of Computer Science Civil Aviation Flight University of ChinaSichuan618307China Anzina PTY Ltd. SydneyNSW 2118Australia

The heterogeneous nodes in the Internet of Things(IoT)are relatively weak in the computing power and storage ***,traditional algorithms of network security are not suitable for the *** these nodes alternate between normal behavior and anomaly behavior,it is difficult to identify and isolate them by the network system in a short time,thus the data transmission accuracy and the integrity of the network function will be affected *** on the characteristics of IoT,a lightweight local outlier factor detection method is used for node *** order to further determine whether the nodes are an anomaly or not,the varying behavior of those nodes in terms of time is considered in this research,and a time series method is used to make the system respond to the randomness and selectiveness of anomaly behavior nodes effectively in a short period of *** results show that the proposed method can improve the accuracy of the data transmitted by the network and achieve better performance.

关键词： Local outlier factor time series Internet of Things anomaly node detection

First-principles investigations of proton generation inα-quartz

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Chinese Physics B 2018年第3期27卷 368-375页

作者： Yunliang Yue Yu Song xu zuo College of Electronic Information and Optical Engineering Nankal UniversityTianjin 300071China Microsystem and Terahertz Research Center China Academy of Engineering PhysicsChengdu 610200China Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang 621999China Municipal Key Laboratory of Photo-electronic Thin Film Devices and Technology Nankai UniversityTianjin 300071China

Proton plays a key role in the interface-trap formation that is one of the primary reliability concerns, thus learning how it behaves is key to understand the radiation response of microelectronic devices. The first-principles calculations have been applied to explore the defects and their reactions associated with the proton release in a-quartz, the well-known crystalline isomer of amorphous silica. When a high concentration of molecular hydrogen （H2） is present, the proton generation can be enhanced by cracking the He molecules at the positively charged oxygen vacancies in dimer configuration. If the concentration of molecular hydrogen is low, the proton generation mainly depends on the proton dissociation of the doubly- hydrogenated defects. In particular, a fully passivated E~ center can dissociate to release a proton barrierlessly by structure relaxation once trapping a hole. This research provides a microscopic insight into the proton release in silicon dioxide, the critical step associated with the interface-trap formation under radiation in microelectronic devices.

关键词： first-principles calculation interface trap proton silicon dioxide

Design and Mechanical Performance Analysis of a New Wheel Propeller

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Chinese Journal of Mechanical Engineering 2011年第5期24卷 805-812页

作者： GAO Fudong PAN Cunyun xu Haijun zuo Xiaobo College oJ＇Mechatronic Engineering and Automation National University of Defense Technology Changsha 410073 China

Nowadays,how to enhance the maneuverability of autonomous underwater vehicles（AUVs） is an important issue in the domain of international navigation in that most AUVs just have a single function of underwater navigation or submarine movement,while the design of thrusters is the key of solving the *** multi-moving state autonomous underwater vehicle in this paper can achieve four functions,such as wheels,legs,thrust,and course control depend on the characteristics of spatial deflexion and continual circumgyratetion of the flexible transmission shaft.A new wheel propeller for the multi-moving state autonomous underwater vehicle is presented through analyzing the mechanical characteristics of the ducted propeller and the contracted and loaded tip（CLT） *** the computational fluid dynamics（CFD） method is used to simulate numerically different propellers open-water performance by using the Reynolds-averaged Navier-Stokes（RANS） equations and Reynolds stress model（RSM） based on sub-domains hybrid *** predicted thrust coefficients,torque coefficients and pressure of the propellers agree well with the experimental data of their open-water *** good consistency shows that the numerical method has good accuracy in the prediction of propeller open-water performance,which guides to design the wheel ***,for the sake of ensuring the security and stability of the AUV when it is moving on the ground,finite element method is used to simulate numerically the intensity and vibration *** proposed final wheel propeller D4-70（WPD4-70） has preferable open-water performance and intensity characteristics,which can realize the agile maneuverability of the multi-moving state autonomous underwater vehicle.

关键词： wheel propeller numerical calculation computational fluid dynamics finite element method