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Corrosion failure analysis of J55 tubing thread fastener in an electric pump well in an oil field
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作者 QI Yameng ZHOU Xiong 《Baosteel Technical Research》 2026年第1期35-39,共5页
The J55 tubing thread fastener in an electric pump well experienced corrosion failure.The causes of the failure were investigated through physical and chemical property tests,corrosion product analysis,and microbial a... The J55 tubing thread fastener in an electric pump well experienced corrosion failure.The causes of the failure were investigated through physical and chemical property tests,corrosion product analysis,and microbial analysis.The results show that the metallographic structure and composition of the J55 tubing were normal.CO 2 corrosion was not the main cause of the thread fastener failure.The actual cause of the corrosion failure was microbiological corrosion,such as sulfate-reducing bacteria,thiosulfate-reducing bacteria,and iron-oxidizing bacteria. 展开更多
关键词 electric pump well tubing thread corrosion perforation microbiological corrosion failure analysis
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Threads of Revival
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作者 HU FAN 《China Today》 2026年第1期50-51,共2页
E-commerce has transformed Caoxian into a hub of traditional Chinese attire.STEPPING inside Caoxian’s Youai Cloud Warehouse,a livestreaming base dedicated to hanfu(traditional clothing),it feels less like a clothing ... E-commerce has transformed Caoxian into a hub of traditional Chinese attire.STEPPING inside Caoxian’s Youai Cloud Warehouse,a livestreaming base dedicated to hanfu(traditional clothing),it feels less like a clothing warehouse and more like a time capsule.Thousands of intricately embroidered garments line the racks-from elegant horse-face skirts to modernised editions of traditional Chinese clothing. 展开更多
关键词 livestreaming base clothing warehouse HANFU livestreaming caoxian threads revival youai cloud warehousea e commerce
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基于Cortex-M4内核的RT-Thread上下文切换机制剖析
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作者 徐丽华 王宜怀 奚圣鑫 《计算机应用与软件》 北大核心 2025年第1期213-216,302,共5页
RT-Thread是源码公开的国产嵌入式实时操作系统。基于Cortex-M4内核,对RT-Thread通过底层PendSV中断进行上下文切换的过程进行了剖析,从指令级别对上下文切换的实现机制进行了研究,为深入理解内核调度机制的实现提供了参考,也为RT-Threa... RT-Thread是源码公开的国产嵌入式实时操作系统。基于Cortex-M4内核,对RT-Thread通过底层PendSV中断进行上下文切换的过程进行了剖析,从指令级别对上下文切换的实现机制进行了研究,为深入理解内核调度机制的实现提供了参考,也为RT-Thread的应用与推广提供了技术基础。 展开更多
关键词 嵌入式实时操作系统 RT-thread 任务调度 上下文切换
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基于RT-Thread的实训室环境监测系统设计 被引量:2
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作者 范宏令 兰岚 刘霄 《山西电子技术》 2025年第1期35-37,66,共4页
实训室是职业院校进行实践教学和科研的重要场所,是改革校企合作模式、培养创新型复合人才和全面提高学生综合职业技能的重要支撑和保障,在职业教育中有着重要地位和作用,实训室安全直接关系着广大师生的生命财产安全,关系着学校和社会... 实训室是职业院校进行实践教学和科研的重要场所,是改革校企合作模式、培养创新型复合人才和全面提高学生综合职业技能的重要支撑和保障,在职业教育中有着重要地位和作用,实训室安全直接关系着广大师生的生命财产安全,关系着学校和社会的安全稳定。本文基于国产物联网操作系统RT-Thread,设计一款实训室环境监测系统,为实训室管理工作提供方便,保障广大师生的生命财产安全。 展开更多
关键词 环境监测 RT-thread NBIOT ZIGBEE 阿里云物联网平台
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Clinical observation on prognosis of mixed hemorrhoids treated with polidocanol injection combined with automatic elastic thread ligation operation 被引量:4
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作者 Yan-Mei Huang Dong Ouyang 《World Journal of Gastrointestinal Surgery》 2025年第1期209-216,共8页
BACKGROUND A total of 100 patients diagnosed with mixed hemorrhoids from October 2022 to September 2023 in our hospital were randomly divided into groups by dice rolling and compared with the efficacy of different tre... BACKGROUND A total of 100 patients diagnosed with mixed hemorrhoids from October 2022 to September 2023 in our hospital were randomly divided into groups by dice rolling and compared with the efficacy of different treatment options.AIM To analyze the clinical effect and prognosis of mixed hemorrhoids treated with polidocanol injection combined with automatic elastic thread ligation operation(RPH).METHODS A total of 100 patients with mixed hemorrhoids who visited our hospital from October 2022 to September 2023 were selected and randomly divided into the control group(n=50)and the treatment group(n=50)by rolling the dice.The procedure for prolapse and hemorrhoids(PPH)was adopted in the control group,while polidocanol foam injection+RPH was adopted in the treatment group.The therapeutic effects,operation time,wound healing time,hospital stay,pain situation(24 hours post-operative pain score,first defecation pain score),quality of life(QOL),incidence of complications(post-operative hemorrhage,edema,infection),incidence of anal stenosis 3 months post-operatively and recurrence rate 1 year post-operatively of the two groups were compared.RESULTS Compared with the control group,the total effective rate of treatment group was higher,and the difference was significant(P<0.05).The operation time/wound healing time/hospital stay in the treatment group were shorter than those in the control group(P<0.05).The pain scores at 24 hours after operation/first defecation pain score of the treatment group was significantly lower than those in the control group(P<0.05).After surgery,the QOL scores of the two groups decreased,with the treatment group having higher scores than that of the control group(P<0.05).Compared with the control group,the incidence of postoperative complications in the treatment group was lower,and the difference was significant(P<0.05);However,there was no significant difference in the incidence of postoperative bleeding between the two groups(P>0.05);There was no significant difference in the incidence of anal stenosis 3 months after operation and the recurrence rate 1 year after operation between the two groups(P>0.05).CONCLUSION For patients with mixed hemorrhoids,the therapeutic effect achieved by using polidocanol injection combined with RPH was better.The wounds of the patients healed faster,the postoperative pain was milder,QOL improved,and the incidence of complications was lower,and the short-term and long-term prognosis was good. 展开更多
关键词 Mixed hemorrhoids Polidocanol injection Automatic elastic thread ligation operation Postoperative hemorrhage The degree of pain Recurrent rate
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基于RT-Thread事件集的多线程相互同步设计方法研究
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作者 索明何 黄鑫 +2 位作者 王宜怀 施连敏 张建 《电脑与信息技术》 2025年第4期71-74,共4页
针对嵌入式系统设计中的多线程相互同步实现问题,提出基于实时操作系统事件集的一般设计算法,给出利用RT-Thread事件集的实现方法和应用实例,最后分析一般设计算法中存在的极端潜在风险,并加以改进,确保设计的可靠性。实践结果表明,所... 针对嵌入式系统设计中的多线程相互同步实现问题,提出基于实时操作系统事件集的一般设计算法,给出利用RT-Thread事件集的实现方法和应用实例,最后分析一般设计算法中存在的极端潜在风险,并加以改进,确保设计的可靠性。实践结果表明,所提出的设计方法具有很好的实时性和可靠性,并具有一定的通用性和参考价值。 展开更多
关键词 多线程相互同步 事件集 事件标志 可靠性
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基于RT-Thread和STM32的多协议工业以太网控制系统设计
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作者 焦钰龙 陈华敏 《计算机应用文摘》 2025年第21期145-148,共4页
文章基于国产RT-Thread操作系统,构建了覆盖“芯片+操作系统+应用”的立体技术生态链。其采用模块化、可扩展架构设计,具备良好的跨硬件平台适应能力与多样化应用场景支持。在以太网协议移植过程中,文章通过集成RT-Thread底层网络驱动... 文章基于国产RT-Thread操作系统,构建了覆盖“芯片+操作系统+应用”的立体技术生态链。其采用模块化、可扩展架构设计,具备良好的跨硬件平台适应能力与多样化应用场景支持。在以太网协议移植过程中,文章通过集成RT-Thread底层网络驱动并配置相关网络组件,实现了稳定可靠的多TCP连接,完成了Modbus-TCP总线通信、FTP文件传输服务器及Web服务器的开发,最终设计并实现了基于RT-Thread与STM32的多协议工业以太网控制系统。该系统具有开发门槛低、设计周期短和成本低等特点,展现出良好的应用前景。 展开更多
关键词 嵌入式 RT-thread系统 工业以太网 LwIP栈 MODBUS总线
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Three-dimensional location approach with silk thread guided hepatectomy for liver tumor
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作者 Zhi-Hong Zhang Qing-Bo Feng +2 位作者 Chuang Jiang Ji-Wei Huang Jia-Xin Li 《World Journal of Gastroenterology》 2025年第8期66-71,共6页
BACKGROUND Intraoperative determination of resection margin and adequate residual liver parenchyma are the key points of hepatectomy for the treatment of liver tumors.Intraoperative ultrasound and indocyanine green fl... BACKGROUND Intraoperative determination of resection margin and adequate residual liver parenchyma are the key points of hepatectomy for the treatment of liver tumors.Intraoperative ultrasound and indocyanine green fluorescence navigation are the most commonly used methods at present,but the technical barriers limit their promotion.AIM To evaluate the value of the three-dimensional location approach with silk thread(3D-LAST)in precise resection of liver tumors.METHODS From September 2020 to January 2022,8 patients with liver tumors including hepatocellular carcinoma,intrahepatic cholangiocarcinoma,hilar cholangiocar-cinoma,and gastric cancer liver metastasis were included in this study.All patients underwent 3D-LAST in precise resection of liver tumors.RESULTS All patients(8/8,100%)underwent the operation successfully without any complications.During the mean follow-up of 8.7 months,all patients survived without tumor recurrence.CONCLUSION In conclusion,the 3D-LAST is a safe and effective new method for liver intraop-erative navigation,which is practical and easy to promote.Core Tip:The aim of this study is to evaluate the value of the three-dimensional location approach with silk thread(3D-LAST)in precise resection of liver tumors.Eight patients with liver tumors including hepatocellular carcinoma,intrahepatic cholangiocarcinoma,hilar cholangiocarcinoma,and gastric cancer liver metastasis underwent the operation successfully without any complications.During the mean follow-up of 8.7 months,all patients survived without tumor recurrence.In conclusion,the 3D-LAST is a safe and effective new method for liver intraoperative navigation,which is practical and easy to promote.INTRODUCTION Hepatectomy is widely used for the treatment of liver tumors.In recent decades,the concept and practice of hepatectomy have developed from irregular,regular and anatomical to the current precise resection.Necessary assistive technologies have enabled these advances.Intraoperative ultrasound(IOUS)localization and indocyanine green(ICG)fluorescence imaging guidance are two frequently-used approaches for laparoscopic hepatectomy[1,2].IOUS is an invaluable auxiliary means widely accepted in surgery for real-time diagnostic information to determine resection range and navigate the surgical path[3].However,the major limitation of IOUS is the time cost during the procedure for paging the sono-graphers and the difficulty of deciphering two dimensional images[4].ICG is a non-toxic water-soluble fluorophore that reveals fluorescence under the near-infrared spectrum[5].Since liver tissue penetration is limited to 5 to 10 mm,that restricted the visualization of deeper tumors by ICG excitation,thereby interfering with its application in laparoscopic hepatectomy[6].IOUS and ICG navigation require specific technical equipment,making implementation difficult in many centers.And these techniques will significantly increase the operation time.Three-dimensional(3D)visualization involves extracting features and producing volumetric images based on computed tomography(CT)through a computer postprocessing technique.This tool offers a reasonable approach to the clinical decision for the potential to display the complex internal anatomy in an intuitive and stereoscopic manner[7].In the past few decades,applying 3D simulation software for liver volume calculation,virtual simulation surgery,portal hypertension monitor,and surgical navigation has proven to be safe and effective[8].Therefore,we propose a new method to find obvious anatomical markers and calculate the resection range according to 3D positioning before operation.During the operation,the scope of resection was delineated with silk thread,and resection was performed.This is a new practical approach,which we named as 3D location approach with silk thread(3D-LAST).RESULTS During the study period from September 2020 to January 2022,5 patients with hepatocellular carcinoma,1 patient with intrahepatic cholangiocarcinoma,1 patient with hilar cholangiocarcinoma,and 1 patient with gastric cancer liver metastasis were assessed for liver resection.There were 5 males and 3 females.The mean age of these patients was 54.3±10.2 years(34-66 years).Preoperative 3D positioning was conducted and the scope of resection was delineated with a surgical suture successfully performed in all 8 patients without complications.The treatment results of these 8 patients are shown in Table 1.The 90-day operative mortality was zero.Complications worse than Dindo-Clavien IIIa was not observed at a mean follow-up time of 8.7 months(4-16 months),there was no evidence of tumor recurrence or extrahepatic metastasis.At the time of reporting,the patients are all alive and lead normal lives.We take one patient as an example,58-year-old male,who found a liver lesion 10 months after gastric cancer surgery.Enhanced CT showed that the lesion was located in the liver S5,about 1.5 cm in diameter,and considered metastatic lesions.We performed 3D-LAST guided hepatectomy on this patient(Figure 1).Other representative 3D-LAST surgical procedures are shown in Figure 2. 展开更多
关键词 HEPATECTOMY LAPAROSCOPY Liver tumor Three dimensional Silk thread
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Research on the mechanism of high-performance gas sealing premium threaded connections
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作者 SUN Jian’an ZHANG Zhonghua GAO Zhan 《Baosteel Technical Research》 2025年第1期28-40,共13页
In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequen... In petroleum extraction,the sealing surfaces of bolted joints are susceptible to damage due to the high-temperature and high-pressure conditions in wellbores.This damage adversely affects sealing performance,consequently leading to the failure and damage of threaded connections.In severe cases,it can result in considerable economic losses and trigger safety accidents.The sealing performance of special bolted joints holds crucial importance for production efficiency,output,equipment lifespan,and cost control.Enhancing the sealing perfor-mance of threaded connections can have a positive impact on industrial production and environmental protection.The existing research on American Petroleum Institute threaded joints has been thorough and has obtained a series of excellent results.However,the research on the sealing damage mechanism of threaded connections under complex well conditions lacks sufficient depth and that on new sealing technology is scarce.This study proposes a half-size evaluation test to address the abovementioned problem.Based on this test,an investigation into the sealing performance of threaded connections under high-temperature,cyclic loading,and high-temperature creep conditions is conducted.This study uses a combined approach of finite element methods and experiments to investigate the impact of different makeup torques on the sealing performance of premium threaded connections(PTCs).The results of the half-size evaluation test indicate that temperature notably influences the sealing performance of threaded connections.The continuous action of high temperatures causes contact pressure and sealing performance to decrease,and sealing contact pressure increases after cooling.Finite element and test results show that for a certain joint A,the greater the torque,the higher the critical sealing pressure of the thread,and the better the sealing performance.The research on the sealing damage mechanism of PTCs provides a scientific basis and theoretical guidance for the further optimization and development of PTCs. 展开更多
关键词 sealing performance premium threaded connection damage mechanism half-size evaluation test
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基于RT-Thread的自平衡自行车系统
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作者 陈欣然 董玉华 +1 位作者 薛严冰 冯冲 《大连民族大学学报》 2025年第3期209-215,共7页
针对裸机模式下开发的自平衡自行车控制系统实时性差、开发周期长、缺乏可移植性等问题,设计了基于RT-Thread的自平衡自行车控制系统。系统以STM32F407为主控芯片,移植RT-Thread对系统软硬件资源进行分配管理,利用RT-Thread线程调度和... 针对裸机模式下开发的自平衡自行车控制系统实时性差、开发周期长、缺乏可移植性等问题,设计了基于RT-Thread的自平衡自行车控制系统。系统以STM32F407为主控芯片,移植RT-Thread对系统软硬件资源进行分配管理,利用RT-Thread线程调度和通信机制实现高实时性控制,同时设计调试辅助系统缩短系统开发周期。实验结果表明:车身在5°的初始状态下起摆可在2.15 s内回正至0°,静止状态车体摆幅在±0.4°,运动状态下车体摆幅不超过±3°,系统线程切换和线程抢占时间最大为10.1μs和12μs,证明该系统平衡控制稳定可靠,实时响应性能较高。 展开更多
关键词 RT-thread 串级PID Mahony互补滤波 微信小程序 OneNET
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Threads of Revival
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作者 HU FAN 《ChinAfrica》 2025年第9期31-33,共3页
When one steps inside Caoxian’s Youai Cloud Warehouse,a livestreaming base dedicated to hanfu,it feels less like a clothing warehouse and more like a time capsule.Thousands of intricately embroidered garments line th... When one steps inside Caoxian’s Youai Cloud Warehouse,a livestreaming base dedicated to hanfu,it feels less like a clothing warehouse and more like a time capsule.Thousands of intricately embroidered garments line the racks-from elegant horse-face skirts to modernised editions of traditional Chinese clothing. 展开更多
关键词 livestreaming base Caoxians Youai Cloud Warehouse clothing warehouse HANFU threadS intricately embroidered garments REVIVAL
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A novel reverse-flow friction stir lap welding of 2024 aluminum alloys based on a right-left thread X-shape pin
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作者 Zhiqing Zhang Kaicheng Lu +5 位作者 Shude Ji Yumei Yue Qi Song Chen Jin Zhenyang Li Lin Ma 《Journal of Materials Science & Technology》 2025年第25期92-106,共15页
For friction stir lap welding (FSLW) process by the rotating pin greatly inserting into the bottom plate, the bending-down morphology of hook helps to obtain a high-strength lap joint, and can be more conducive to the... For friction stir lap welding (FSLW) process by the rotating pin greatly inserting into the bottom plate, the bending-down morphology of hook helps to obtain a high-strength lap joint, and can be more conducive to the joint strength when the tensile-fractured path is located in the top plate. In light of this, the reverse-flow FSLW (RF-FSLW) by a newly designed rotating tool with a right-left threaded X-shape pin (X-pin) was employed to weld 2024-T4 aluminum alloys with the same plate thickness, and the flow field simulation, in situ tensile test and EBSD analysis were utilized to understand the relations among the formation features, the fracture features and the joint strengths. The results indicated that under the integrated effects of the bending-down shape of hook, the bulging shape of nugget zone (NZ) and the bending-up shape of beginning part of cold lap near NZ outline, the RF-FSLW joint was tensile fractured in the top plate of joint. For the RF-FSLW joint, its maximum tensile strength was 412 MPa, and the corresponding joint efficiency (92.8%) was larger than that of reported friction stir welded joint of 2024 aluminum alloys in T temper condition. The RF-FSLW technology by the right-left threaded X-pin puts forward an extremely effective way for obtaining the superb-strength lap joint of aluminum alloys. 展开更多
关键词 Reverse-flow friction stir lap welding 2024-T4 aluminum alloy Right-left threaded X-pin Hook Tensile strength
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Small market but big potential:How sewing threads are weaving the future of automotive interiors and outdoor gear
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作者 Zhong Mengxia 《China Textile》 2025年第4期22-23,共2页
As the global textile market continues to expand, demand for sewing threads-a critical auxiliary material-is rising. In recent years, automotive interiors, smart outdoor equipment, and medical and ecofriendly products... As the global textile market continues to expand, demand for sewing threads-a critical auxiliary material-is rising. In recent years, automotive interiors, smart outdoor equipment, and medical and ecofriendly products have emerged as new growth engines for the textile industry. This has propelled specialized niche markets for sewing threads designed for these applications, revealing significant and undeniable potential. 展开更多
关键词 interiorssmart outdoor equipmentand automotive interiors smart outdoor equipment sewing threads eco friendly products textile industry medical products
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发动机铝合金缸体螺纹孔拧紧过程中的应力与变形分析
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作者 邓伟 但林坪 +3 位作者 雷基林 贾德文 侯飞 张勇 《机械科学与技术》 北大核心 2026年第2期324-337,共14页
发动机缸体与缸盖通过螺栓连接,缸体螺纹孔为轻量化材质,采用钢质螺栓拧紧时,其螺纹孔的应力与变形对缸体缸盖连接有着重要影响,进而影响发动机的运行可靠性。为此建立考虑详细螺纹的铝合金缸体螺纹连接精细有限元模型,可用于模拟实际... 发动机缸体与缸盖通过螺栓连接,缸体螺纹孔为轻量化材质,采用钢质螺栓拧紧时,其螺纹孔的应力与变形对缸体缸盖连接有着重要影响,进而影响发动机的运行可靠性。为此建立考虑详细螺纹的铝合金缸体螺纹连接精细有限元模型,可用于模拟实际拧紧过程,讨论铝合金缸体螺纹孔拧紧时应力与变形分布状态。利用该模型分析了螺纹孔壁厚对紧固扭矩与紧固轴力之间关系的影响;分析了螺纹孔壁厚和紧固扭矩对缸体螺纹孔拧紧时应力与变形的影响。结果表明:壁厚对紧固轴力影响不显著。当壁厚与螺纹中径比值Φ/D2≥0.455时,内螺纹各螺纹牙根部和啮合第一螺纹横截面的应力分别随螺纹牙序号和径向半径呈单相指数型衰减。减小壁厚增大了螺纹孔应力集中区域和螺纹牙综合变形量。在铝合金缸体螺纹孔拧紧过程中啮合第一螺纹等效应力达到其材料抗拉强度的27.7%~34.2%时出现相对明显的塑性变形;螺纹孔塑性变形主要集中在螺牙根部,呈W型分布。基于研究结果,建议铝合金缸体螺纹孔壁厚与螺纹中径比值不小于0.455。 展开更多
关键词 发动机 螺纹连接 螺纹孔 拧紧过程 应力 变形
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螺纹结构对螺纹桩双桩竖向承载特性的影响研究
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作者 徐丽娜 张鹏 孙爽 《湖南大学学报(自然科学版)》 北大核心 2026年第3期88-98,共11页
基于三维有限元数值模拟分析,建立了竖向荷载下双桩的数值分析模型,研究了不同设计参数(包括桩间距、螺牙高度、螺纹段长度)对螺纹桩双桩竖向承载特性的影响,分析了桩周土体位移云图的变化规律,揭示了桩身轴力传递特性,并结合承载力提... 基于三维有限元数值模拟分析,建立了竖向荷载下双桩的数值分析模型,研究了不同设计参数(包括桩间距、螺牙高度、螺纹段长度)对螺纹桩双桩竖向承载特性的影响,分析了桩周土体位移云图的变化规律,揭示了桩身轴力传递特性,并结合承载力提升效果与材料利用率探究了螺纹结构的最佳设计区间.结果表明:随着桩间距的增加,桩间的相互干扰效应减小,双桩承载力随之增加,桩间距为4~5倍桩外径时双桩承载性能较好;增加螺牙高度会加强螺纹与土的机械咬合作用,进而提升双桩承载力,螺牙高度与桩内径的比值为0.5~0.6时双桩承载能力得到充分发挥;增加螺纹段长度能够有效增加桩-土体的接触面积,桩的侧摩阻力增强,从而提升双桩承载力与桩身材料利用率,螺纹段长度与桩长比值为0.6~0.7时的双桩承载性能最佳;提高螺纹段长度是提高双桩承载力最有效的途径. 展开更多
关键词 螺纹桩双桩 螺纹结构设计 承载力 材料利用率 数值模拟
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HS-SPME-GC-MS结合多元统计分析对金银花线香燃烧产物的鉴定
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作者 张颖 及华 +2 位作者 李梦雪 于文龙 章丽 《中国农业科技导报(中英文)》 北大核心 2026年第1期242-254,共13页
为鉴定线香中主要挥发性成分,进一步揭示这些成分在不同样品间的差异及其对香气特征的贡献,采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)结... 为鉴定线香中主要挥发性成分,进一步揭示这些成分在不同样品间的差异及其对香气特征的贡献,采用顶空固相微萃取-气相色谱-质谱联用技术(headspace solid-phase microextraction gas chromatography-mass spectrometry,HS-SPME-GC-MS)结合多元统计分析方法对粘粉燃烧产物、金银花粉、金银花粉燃烧产物、线香燃烧产物中挥发性成分进行提取鉴定,并确定关键挥发性成分。结果表明,从4种样品中共鉴定出102种挥发性成分,以芳香族、杂环类、酮类化合物等成分为主。主成分分析、正交偏最小二乘法判别分析及聚类热图分析表明,金银花粉燃烧产物和线香燃烧产物挥发性成分组成相似,与粘粉燃烧产物及金银花粉挥发性成分存在较大差异,并筛选出25种投影变量的重要性(variable important for the projection,VIP)>1的关键挥发性成分。研究结果为金银花线香的进一步开发提供理论依据,也为中药材的应用拓展了新方向。 展开更多
关键词 金银花 线香 挥发性成分 多元统计分析
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基于分形理论的锥面-锥面特殊螺纹接头密封性能研究
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作者 曹银萍 刘王恒 +1 位作者 于洋 唐家睿 《润滑与密封》 北大核心 2026年第2期1-9,共9页
现有的特殊螺纹接头有限元分析大多建立在密封面完全光滑的基础上,未考虑密封面的微观形貌。为研究粗糙密封面对锥面-锥面特殊螺纹接头密封性能的影响,基于Weierstrass-Mandelbrot分形函数,建立包含粗糙密封面的特殊螺纹接头有限元模型... 现有的特殊螺纹接头有限元分析大多建立在密封面完全光滑的基础上,未考虑密封面的微观形貌。为研究粗糙密封面对锥面-锥面特殊螺纹接头密封性能的影响,基于Weierstrass-Mandelbrot分形函数,建立包含粗糙密封面的特殊螺纹接头有限元模型,研究密封面粗糙度、上扣扭矩及内压载荷对接头密封性能的影响。结果表明:最佳上扣扭矩下,粗糙密封面上的接触压力存在多个局部峰值,随着粗糙度减小,真实接触长度逐渐增大,接触压力分布更均匀;同一粗糙度下,随着上扣扭矩的增大,密封面真实接触长度增大,在保证结构强度安全的前提下,减小粗糙度和适当增大上扣扭矩,有利于提高接头的密封性能;随着内压的增加,粗糙密封面上产生接触的微凸体数量增多,产生塑性流动的微小间隙被塑性流动金属填充,因此真实接触长度增大,特殊螺纹接头密封性能增强。研究结果为特殊螺纹接头微观形貌下的密封性能分析提供参考。 展开更多
关键词 特殊螺纹接头 密封性能 分形理论 密封面 粗糙度
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镶套多向顺序抽芯及自动脱螺纹注塑模具设计
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作者 陈亚洲 荣星 蔡部林 《工程塑料应用》 北大核心 2026年第2期138-146,共9页
某塑料接头内部设计了3组互相垂直贯通孔的结构。在塑件一个端面,分布的2个贯通孔、2个盲孔方向一致,与另外1个贯通孔方向呈一定夹角,为此设计了镶套2个方向的复合抽芯机构,解决了空间狭小、抽芯运动受限、机构相互干涉的问题,利用斜导... 某塑料接头内部设计了3组互相垂直贯通孔的结构。在塑件一个端面,分布的2个贯通孔、2个盲孔方向一致,与另外1个贯通孔方向呈一定夹角,为此设计了镶套2个方向的复合抽芯机构,解决了空间狭小、抽芯运动受限、机构相互干涉的问题,利用斜导柱、弯销分别驱动两组抽芯机构运动,实现了准确的顺序控制。在塑件另一垂直端面,分布了3个方向一致的贯通孔,一个为阶梯孔,另2个孔内有Rc1/8-LH管螺纹,为此设计了液压马达驱动自动脱螺纹机构。为防止螺纹型芯、料头杆旋转时,与其支撑件的配合面摩擦而磨损,设计了动模板与脱模机构固定板之间第1次开模距离1 mm,使得启动脱螺纹时,螺纹型芯、料头杆能够快速后退1 mm,与其支撑件的配合面脱离;定模板与动模板之间第2次开模距离为7 mm,达到解锁定距开闭器目的,使得脱模机构固定板可活动;塑件对阶梯型芯的包紧力与脱螺纹作用力方向相反,为解决脱螺纹时塑件被拉坏的问题,设计了在脱模机构固定板与动模垫板之间第3次开模距离6 mm,让固定于动模垫板的阶梯型芯脱离塑件;在定模板与动模板之间继续第4次开模,驱动复合抽芯机构完成抽芯动作,直至开模完成。为保证模具的各项功能实施,设计了纯机械结构控制的3位4次开模顺序,加工制造成本低,安装调试简单方便。塑件材质为质量分数60%玻璃纤维增强聚己内酰胺,其表面容易产生浮纤,为此设计了合理的进浇系统、排气系统及冷却系统,以保证塑件产品质量。 展开更多
关键词 多向顺序抽芯 自动脱螺纹机构 注塑模具
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循环荷载下精轧螺纹钢抗浮锚杆锚固性能原位试验研究
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作者 闫楠 白晓宇 +3 位作者 杜焕龙 孙淦 刘俊伟 张明义 《中南大学学报(自然科学版)》 北大核心 2026年第1期360-375,共16页
依托青岛市某深基坑工程,进行3根精轧螺纹钢抗浮锚杆的现场拉拔破坏性试验,研究多循环荷载作用下精轧螺纹钢抗浮锚杆的荷载传递机制与锚固特征。研究结果表明,在本试验条件下,精轧螺纹钢抗浮锚杆在循环荷载作用中表现出显著的弹性特征,... 依托青岛市某深基坑工程,进行3根精轧螺纹钢抗浮锚杆的现场拉拔破坏性试验,研究多循环荷载作用下精轧螺纹钢抗浮锚杆的荷载传递机制与锚固特征。研究结果表明,在本试验条件下,精轧螺纹钢抗浮锚杆在循环荷载作用中表现出显著的弹性特征,其荷载-位移关系呈现典型的滞回曲线形态,且卸载阶段具有较高的变形恢复能力。锚杆杆体轴力作用范围主要在孔口以下10.0 m范围内;在相同荷载下,锚杆杆体轴力随锚固深度的增加而逐渐衰减;在相同锚固深度处,随荷载及循环次数增加,锚杆杆体轴力增大,且杆体轴力零值点的位置逐渐向锚杆深部转移。锚杆杆体的剪应力整体呈先增大后减小的趋势,剪应力峰值随荷载水平以及循环次数的增加而向杆体深部移动。 展开更多
关键词 精轧螺纹钢筋 抗浮锚杆 循环加载试验 锚固性能 轴力 剪应力
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基于经筋理论运用分层透刺埋线法治疗膝骨关节炎
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作者 王雪霞 郭翔 +2 位作者 梁爽 郭现辉 何臻子 《河南中医》 2026年第3期355-359,共5页
膝骨关节炎特点是筋骨共病、痿痹共存,主要表现为膝关节疼痛、肿胀和功能障碍等。分层透刺埋线注重埋线部位下方的组织层次,注重线体所在位置,具体埋线深度根据不同的穴位、治疗的目的、不同的人而异。基于分层透刺埋线理论,结合疾病的... 膝骨关节炎特点是筋骨共病、痿痹共存,主要表现为膝关节疼痛、肿胀和功能障碍等。分层透刺埋线注重埋线部位下方的组织层次,注重线体所在位置,具体埋线深度根据不同的穴位、治疗的目的、不同的人而异。基于分层透刺埋线理论,结合疾病的表里层次、病位深度、腧穴及穴位解剖结构选取合适长度的线体进行操作,在治疗膝骨关节炎时,需选取1-3cm不等线体以对折法分别埋置于浅层(肌肉筋膜)与深层(肌腱韧带)。分层透刺埋线法突破传统埋线“以痛为腧”的局限,将中医经筋理论与现代运动链理论结合,提出“肌-筋”分层治疗,治疗时选用肝、胆、脾、胃、肾经穴位:环跳、阳陵泉、阴陵泉、血海、阴谷、足三里、三阴交。目前,分层透刺埋线治疗膝骨关节炎仍停留在经验层面,尚未完全形成量化标准,未来可以考虑线体长度与层次精准化,针对不同解剖结构选取不同的线体长度进行针对性操作,未来需通过高质量临床研究与机制探索,进一步优化该技术的标准化与个体化应用。 展开更多
关键词 膝骨关节炎 分层透刺埋线法 经筋理论
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