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硬质合金刀具皮秒激光加工表面形貌及成分变化研究

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工具技术 2024年第5期58卷 26-31页

作者：洪云王成勇邓阳赖志伟刘宇华广东工业大学机电工程学院广州市510000 高性能工具全国重点实验室

聚焦于硬质合金皮秒激光加工表面成分变化特性,研究了不同激光能流密度对硬质合金表面形貌、粗糙度、材料去除特性和化学成分的影响,重点讨论了烧结WC-Co硬质合金在皮秒激光加工前后的表面特性,获得不同能流密度激光与WC-Co材料的作用机... 详细信息

聚焦于硬质合金皮秒激光加工表面成分变化特性,研究了不同激光能流密度对硬质合金表面形貌、粗糙度、材料去除特性和化学成分的影响,重点讨论了烧结WC-Co硬质合金在皮秒激光加工前后的表面特性,获得不同能流密度激光与WC-Co材料的作用机制,结果表明,在低能流密度下,激光与WC-Co的作用机制主要是浅表层熔化机制,属于激光抛光,在WC-Co刀具激光加工中可用作精加工工序;在高能流密度下,激光与WC-Co的作用机制主要在材料深度方向稳定去除,在WC-Co刀具激光加工中可用作粗加工工序。本研究为WC-Co刀具的激光加工提供了理论参考和数据支持。

关键词：硬质合金刀具超快激光能流密度表面形貌元素成分

Interfacial Structure and Formation Mechanism of Ultrasonic-assisted Brazed Joint of SiC Ceramics with Al—12Si Filler Metals in Air

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Journal of Materials Science & Technology 2017年第5期33卷 492-498页

作者： Xiaoguang Chen Ruishan Xie zhiwei lai Lei Liu Jiuchun Yan Guisheng Zou State Key Laboratory of Advanced Welding and Joining School of Materials Science and Engineering Harbin Institute of Technology Department of Mechanical Engineering Key Laboratory for Advanced Manufacturing by Materials Processing Technology Tsinghua University College of Material Science and Engineering Taiyuan University of Technology

Ultrasonic-assisted brazing of SiC ceramics was performed by filling with an Al-12Si alloy at a low tem- perature of 620 ℃ in air. The interracial characteristics and formation mechanism were investigated. The joint shear strength reached 84-94 MPa using the ultrasonic time of 2-16 s. The fracture morphology showed that the fracture path initiated and propagated in the joint alloy. The thin film of amorphous SiO2 that formed on the SiC surface was non-uniformly decomposed and diffused into the liquid Al-12Si alloy under the cavitation erosion effect of ultrasound. Abnormal isolated blocks of A12SiO5 compounds formed at the interface between Al-12Si and a thicker SiO2 layer formed during the thermal oxidation treatment of the SiC ceramic. The SiO2 layer on the SiC ceramic did not hinder or impair the wetting and bonding process, and a stronger bond could form between Al-12Si and SiO2 or SiC in ultrasonic- assisted brazing.

关键词： Ultrasonic Brazing Ceramic Interface Cavitation erosion

Ultrasound-Assisted Transient Liquid Phase Bonding of Magnesium Alloy Using Brass Interlayer in Air

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Journal of Materials Science & Technology 2017年第6期33卷 567-572页

作者： zhiwei lai Ruishan Xie Chuan Pan Xiaoguang Chen Lei Liu Wenxian Wang Guisheng Zou School of Materials Science and Engineering Tsinghua University Department of Mechanical Engineering Key Laboratory for Advanced Manufacturing by Materials Processing Technology Tsinghua University China Iron & Steel Research Institute Group R&D Department Yongtai Electric (Dong Guan) Co. Ltd College of Materials Science and Engineering Shanxi Key Laboratory of Advanced Magnesium-based Materials Taiyuan University of Technology

The microstructure evolution and oxide film behavior in ultrasound-assisted transient liquid phase（U-TLP） bonding of Mg alloy were investigated by applying different ultrasonic time at 460？C with brass interlayer in air. The results indicated that with increasing ultrasonic time, brass interlayer disappeared gradually and the Mg-Cu-Zn eutectic compounds were formed. The eutectic compounds in the joint decreased as the ultrasonic time increased further. The oxide removal process was divided into four steps. Continuous oxide film at the interface was partially fractured by ultrasonic vibration,and then suspended into liquid by undermining eutectic reaction. After that, the suspended oxide film was broken into small oxide fragments by ultrasonic cavitation effect, which was finally squeezed out of the joint by ultrasonic squeeze action. In addition, the mechanical properties of the joints were investigated. The maximum shear strength of the joint reached 105 MPa, which was 100% of base metal.

关键词： Magnesium alloy Bonding Ultrasound Oxide film Microstructure

Automated Determination of Cd^(2+) and Pb^(2+) in Natural Waters with Sequential Injection Analysis Device Using Differential Pulse Anodic Stripping Voltammetry

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Journal of Analysis and Testing 2021年第1期5卷 60-68页

作者： zhiwei lai Fangyuan Lin Yipeng Huang Yiru Wang Xi Chen MOE Key Laboratory of Spectrochemical Analysis and Instrumentation College of Chemistry and Chemical EngineeringXiamen UniversityXiamen 361005China State Key Laboratory of Marine Environmental Science Xiamen UniversityXiamen 361005China

An electrochemical flow device has been developed for the determination of heavy metal ions(HMI)in water using multiwalled carbon nanotubes(MWCNTs)/Nafion(NA)/Hg electrode,by mean of diff erential pulse anodic stripping voltammetry coupled with sequential injection *** accuracy of the determination was ensured by the great electrical conductivity of MWCNTs and the high adsorption capacity of *** was used for MWCNTs immobilization for the long-term application of the *** mercury film was cleaned after determination and another one would form during deposition.A lower limit of detection and a wider determination range of Cd^(2+)and Pb^(2+)could be achieved using the automatically analytical device combining with the MWCNTs/NA/Hg-modified *** real-time monitoring of Cd^(2+)and Pb^(2+)in fresh water using this device continued for 10 *** results indicated that the method was potential for on-site and real-time determination of HMI in water samples.

关键词： Electrochemical flow device Differential pulse anodic stripping voltammetry Cd^(2+) Pb^(2+) Water samples

2023年中国部分预防接种单位疫苗存储发送自动化系统应用调查

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中国疫苗和免疫 2024年第3期30卷 328-332页

作者：谢超赖智维杨威唐宁甘明方兴刘捷宸张伟燕朱琦湖南省疾病预防控制中心湖南长沙410153 中国科学院沈阳自动化研究所辽宁沈阳110169 贵州省疾病预防控制中心贵州贵阳550004 广西壮族自治区疾病预防控制中心广西南宁530028 辽宁省疾病预防控制中心辽宁沈阳110005 上海市疾病预防控制中心上海200336 山东省疾病预防控制中心山东济南250014 广东省疾病预防控制中心广东广州511430

目的了解预防接种单位疫苗存储发送自动化系统(Automatic vaccine storage and distribution system,AVSDS)应用现状。方法选取2023年中国使用AVSDS的预防接种门诊开展问卷调查,分析AVSDS使用前后工作效率和预防接种单位工作人员对系统... 详细信息

目的了解预防接种单位疫苗存储发送自动化系统(Automatic vaccine storage and distribution system,AVSDS)应用现状。方法选取2023年中国使用AVSDS的预防接种门诊开展问卷调查,分析AVSDS使用前后工作效率和预防接种单位工作人员对系统功能的必要性、满意度和应用效果评分(满分分别为9分、5分和5分)。结果在87家调查预防接种单位中,AVSDS使用前、后平均每工作台每小时疫苗接种量分别为18.30±3.22剂次、18.34±2.41剂次(t=0.11,P=0.915),接种日疫苗库存盘点时间<30 min的预防接种单位比例分别为35.63%、100%(χ^(2)=82.58,P<0.001),疫苗扫码出入库时间<60 min的预防接种单位比例分别为39.08%、73.56%(χ^(2)=21.03,P<0.001)。预防接种单位对AVSDS 9项功能的必要性平均评分在5.33-8.14分之间,满意度平均评分在3.25-4.39分之间;对6个方面应用效果的平均评分在4.31-4.64分之间。结论AVSDS现有功能基本满足调查预防接种单位的日常服务需求,一定程度提升了预防接种效率和质量。

关键词：预防接种预防接种单位疫苗存储发送自动化系统应用

基于2020-2022年湖南省健康人群免疫水平监测的免疫程序调整对流行性腮腺炎抗体水平影响分析

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疾病监测 2024年第7期39卷 940-944页

作者：赖智维张淑君方明礼李芳彩尹雯莲刘红专沈吟湖南省疾病预防控制中心湖南长沙410005 岳阳县疾病预防控制中心湖南岳阳414100 桃源县疾病预防控制中心湖南常德415700 沅江市疾病预防控制中心湖南益阳413100

目的分析免疫程序调整对湖南省健康人群流行性腮腺炎抗体水平的影响,为评估2剂次含腮腺炎成分疫苗(MuCV)免疫策略的短期免疫效果提供依据。方法数据来源于2020—2022年湖南省流行性腮腺炎人群免疫水平监测数据,将免疫程序调整后完成2剂... 详细信息

目的分析免疫程序调整对湖南省健康人群流行性腮腺炎抗体水平的影响,为评估2剂次含腮腺炎成分疫苗(MuCV)免疫策略的短期免疫效果提供依据。方法数据来源于2020—2022年湖南省流行性腮腺炎人群免疫水平监测数据,将免疫程序调整后完成2剂次MuCV接种的监测对象作为2剂次组,根据2剂次组的年龄范围选择仅完成1剂次MuCV接种的监测对象作为1剂次组,计算并比较两组间IgG抗体阳性率和抗体几何平均浓度(GMC)的差异。结果本研究共纳入符合条件的对象169人,其中2剂次组73人,1剂次组96人。两组间性别、年龄、采样距末次MuCV接种时间间隔的分布差异均无统计学意义(χ^(2)=0.002、3.618、0.757,P=0.963、0.164、0.685)。2剂次组抗体阳性率为98.63%,高于1剂次组的81.25%,差异有统计学意义(χ^(2)=12.553,P<0.05)。2剂次组抗体GMC为928.48 IU/mL,高于1剂次组的265.89 IU/mL,差异有统计学意义(H=47.659,P<0.05)。结论实施2剂次MuCV接种免疫策略后,湖南省1~3岁人群腮腺炎IgG抗体阳性率和抗体GMC均有明显提高,短期内抗体GMC随时间下降不明显。但免疫策略调整对腮腺炎抗体水平的长期免疫持久性和对减少流行性腮腺炎发病的作用,均需进一步观察。

关键词：流行性腮腺炎免疫程序调整 IgG抗体水平

回风巷道风雾联合降尘装置喷雾雾化规律和抑制粉尘研究

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煤矿机械 2024年第4期45卷 45-48页

作者：来志伟李玉福王杰聂文李建军国家能源集团神东煤炭集团安监局内蒙古鄂尔多斯017209 山东科技大学安全与环境工程学院山东青岛266590

为有效解决综采工作面产生的高浓度粉尘向回风巷道扩散的问题,研制了一种可移动风雾联合降尘装置。首先通过喷雾实验选出合适的喷嘴并验证数值模拟的有效性,然后通过正交试验的方法,运用FLUENT等软件进行模拟,分析喷雾压力p_(w)、喷嘴孔... 详细信息

为有效解决综采工作面产生的高浓度粉尘向回风巷道扩散的问题,研制了一种可移动风雾联合降尘装置。首先通过喷雾实验选出合适的喷嘴并验证数值模拟的有效性,然后通过正交试验的方法,运用FLUENT等软件进行模拟,分析喷雾压力p_(w)、喷嘴孔径D和吸风口吸风量Q对雾场浓度的影响规律。模拟结果显示,p_(w)=8 MPa、D=Ф2.4 mm、Q=1.4 m^(3)/s为最佳参数组合。最后在上湾煤矿12305综采工作面回风巷进行现场实测,得出平均降尘率达到了85%,说明该装置可以有效解决回风巷道粉尘污染问题。

关键词：回风巷道风-雾联合降尘数值模拟正交试验

Evaluation of laboratory and environmental exposure systems for protein modification upon gas pollutants and environmental factors

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Journal of Environmental Sciences 2024年第9期143卷 213-223页

作者： zhiwei Pan ShiyiWu Qiaoze Zhu Fobang Liu Yongjian Liang Chenglei Pei Haoyu Jiang Yingyi Zhang Senchao lai The Key Lab of Pollution Control and Ecosystem Restoration in Industry Clusters Ministry of EducationSchool of Environment and EnergySouth China University of TechnologyGuangzhou 510006China Department of Environmental Science and Engineering Xi’an Jiaotong UniversityXi’an 710049China Guangzhou Sub-branch of Guangdong Ecological and Environmental Monitoring Center Guangzhou 510006China State Key Laboratory of Organic Geochemistry Guangdong Key Laboratory of Environmental Protection and Resources Utilizationand Joint Laboratory of the Guangdong-Hong Kong-Macao Greater Bay Area for the EnvironmentGuangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China School of Marine Sciences Sun Yat-sen UniversityZhuhai 519082China

Chemical modifications of proteins induced by ambient ozone(O_(3))and nitrogen oxides(NOx)are of public health concerns due to their potential to trigger respiratory *** laboratory and environmental exposure systems have been widely used to investigate their relevant mechanism in the *** bovine serum albumin(BSA)as a model protein,we evaluated the two systems and aimed to reduce the uncertainties of both the reactants and products in the corresponding kinetic *** the laboratory simulation system,the generated gaseous pollutants showed negligible *** layers of BSA were coated on the flow tube with protein extraction recovery of 87.4%.For environmental exposure experiment,quartz fiber filter was selected as the upper filter with low gaseous O_(3)(8.0%)and NO_(2)(1.7%)losses,and cellulose acetate filter was appropriate for the lower filter with protein extraction efficiency of 95.2%.The protein degradation process was observed without the exposure to atmospheric oxidants and contributed to the loss of protein monomer mass fractions,while environmental factors(e.g.,molecular oxygen and ultraviolet)may cause greater protein monomer *** on the evaluation,the study exemplarily applied the two systems to protein modification and both showed that O_(3) promotes the protein oligomerization and nitration,while increased temperature can accelerate the oligomerization and increased relative humidity can inhibit the nitration in the environmental exposure *** developed laboratory and environmental systems are suitable for studying protein modifications formed under different atmospheric conditions.A combination of the two will further reveal the actual mechanism of protein modifications.

关键词： Protein modification Laboratory simulation Environmental exposure Oligomerization Nitration

A Simplified Electrochemical Instrument Equipped with Automated Flow-injection System for Determination of Heavy Metal Ions

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A Simplified Electrochemical Instrument Equipped with Automa...