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Bone graft incorporation failure with inappropriate limb load transfer can lead to aseptic acetabular loosening of metal-on-metal prosthesis: A case report
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作者 RafałStanisław Domagalski Bogdan Dugiełło +6 位作者 Sonia Rokicka Szymon Czech RafałSkowroński Dominika Rokicka Marta Patrycja Wróbel Krzysztof Strojek Tomasz Stołtny 《World Journal of Orthopedics》 2024年第7期668-674,共7页
BACKGROUND Aseptic acetabular loosening can result from various factors that can be categorized into groups:patient-related,surgeon-related and implant-related.We present a case of a 63-year-old patient who at first u... BACKGROUND Aseptic acetabular loosening can result from various factors that can be categorized into groups:patient-related,surgeon-related and implant-related.We present a case of a 63-year-old patient who at first underwent a total hip arthro-plasty(THA)using a metal-on-metal bearing due to hip arthrosis.Follow-up visits revealed no complications after the procedure.Two years after the THA,acetabular component loosening occurred due to subsequent trauma of the opposite hip,necessitating a revision THA using a ceramic-on-ceramic bearing.CASE SUMMARY We aim to illustrate a rare case where the primary reason for undergoing THA revision was not only incomplete bone graft incorporation but also improper limb load distribution.Following the revision arthroplasty,a 9-year follow-up visit revealed improvements in all evaluation measures on questionnaire compared to the state before surgery:Harris Hip Score(before surgery:15;after surgery:95),Western Ontario and McMaster Universities Arthritis Index(before surgery:96;after surgery:0),and Visual Analogue Scale(before surgery:10;after surgery:1).CONCLUSION Opposite-hip trauma caused a weight transfer to the limb after a THA procedure.This process led to a stress shielding effect,resulting in acetabular component loosening. 展开更多
关键词 Acetabular loosening Limb load Stress shielding effect Revision hip arthroplasty Case report
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Effect of Deep Loosening on Soil Structure and Maize Root Activity 被引量:2
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作者 闫伟平 边少锋 +6 位作者 谭国波 赵洪祥 李海 张丽华 方向前 孟祥盟 孙宁 《Agricultural Science & Technology》 CAS 2016年第11期2539-2542,2545,共5页
[Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water res... [Objective] This study was conducted to explore the effects of deep loos- ening on soil structure and the activity of maize root system, to provide a theoreti- cal basis for the efficient and rational use of water resources. [Method] Three differ- ent loosening treatments for maize in ridges were performed in field trials as fol- lows: conventional ridge tillage, loosening the cm in spring (deep loosening in spring), and depth of 30 cm in autumn (deep loosening in soils between rows to a depth of 30 oosening the soils between rows to a autumn). Then the soil properties and the development of root system were measured to evaluate the effects of different loosening methods. [Result] Soil compactness was significantly reduced after deep loosening in spring, There were significant differences in soil compactness in 0-20 cm depth and soil bulk density in 0-40 cm depth between deep loosening in spring and deep loosening in autumn, deep loosening in spring and conventional ridge tillage. The soil water holding capacity was also significantly different between the two deep loosening treatments and conventional ridge tillage. Moreover, the root ac- tive absorption area of maize of deep loosening in spring was higher than that of conventionai ridge tillage. [Conclusion] Deep loosening can reduce soil compactness, bulk density, and improve soil water holding capacity, soil water content and the root activity of maize. Deep loosening in spring is better in soil improvement be- cause spring is closer to the growth period of crops than autumn. So, deep loosen- ing is conducive to the improvement of soil compactness and structure. 展开更多
关键词 Deep loosening Soil compactness Soil water content Root active ab- sorotion area
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RANK-ligand and osteoprotegerin as biomarkers in the differentiation between periprosthetic joint infection and aseptic prosthesis loosening 被引量:4
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作者 Max J Friedrich Matthias D Wimmer +6 位作者 Jan Schmolders Andreas C Strauss Milena M Ploeger Hendrik Kohlhof Dieter C Wirtz Sascha Gravius Thomas M Randau 《World Journal of Orthopedics》 2017年第4期342-349,共8页
AIM To assess serum levels of RANK-ligand(RANKL) and osteoprotegerin(OPG) as biomarkers for periprosthetic joint infection(PJI) and compare their accuracy with standard tests.METHODS One hundred and twenty patients pr... AIM To assess serum levels of RANK-ligand(RANKL) and osteoprotegerin(OPG) as biomarkers for periprosthetic joint infection(PJI) and compare their accuracy with standard tests.METHODS One hundred and twenty patients presenting with a painful total knee or hip arthroplasty with indication for surgical revision were included in this prospective clinical trial. Based on standard diagnostics(joint aspirate, microbiological, and histological samples) and Musculoskeletal Infection Society consensus classification,patients were categorized into PJI, aseptic loosening,and control groups. Implant loosening was assessed radiographically and intraoperatively. Preoperative serum samples were collected and analyzed for RANKL, OPG, calcium, phosphate, alkaline phosphatase(AP), and the bone-specific subform of AP(b AP). Statistical analysis was carried out, testing for significant differences between the three groups and between stable and loose implants. RESULTS All three groups were identical in regards to age, gender, and joint distribution. No statistically significant differences in the serum concentration of RANKL(P = 0.16) and OPG(P = 0.45) were found between aseptic loosening and PJI, with a trend towards lower RANKL concentrations and higher OPG concentrations in the PJI group. The RANKL/OPG ratio was significant for the comparison between PJI and non-PJI(P = 0.005). A ratio > 60 ruled out PJI in all cases(specificity: 100%, 95%CI: 89, 11% to 100.0%) but only 30% of non-PJI patients crossed this threshold. The positive predictive value remained poor at any cut-off. In the differentiation between stable and loose implants, none of the parameters measured(calcium, phosphate, AP, and b AP) showed a significant difference, and only AP and b AP measurements showed a tendency towards higher values in the loosened group(with P = 0.09 for AP and P = 0.19 for b AP). CONCLUSION Lower RANKL and higher OPG concentrations could be detected in PJI, without statistical significance. 展开更多
关键词 ASEPTIC loosening Diagnostic RANK-ligand PERIPROSTHETIC joint infection Biomarker OSTEOPROTEGERIN
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Competitive Failure of Bolt Loosening and Fatigue under Different Preloads 被引量:1
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作者 Guangwu Yang Long Yang +2 位作者 Jingsong Chen Shoune Xiao Shilin Jiang 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2021年第6期417-427,共11页
Existing research on the competitive failure relationship,failure mechanism,and influencing factors of bolt loosening and fatigue under different preloads is insufficient.This study analyzes the competitive failure re... Existing research on the competitive failure relationship,failure mechanism,and influencing factors of bolt loosening and fatigue under different preloads is insufficient.This study analyzes the competitive failure relationship between bolt loosening and fatigue under composite excitation through competitive failure tests of bolt loosening and fatigue under different preloads.The results indicated that the failure mode of the bolt is only related to the load ratio(R)and is unrelated to the initial preload and excitation amplitude,which only determine the failure life of the bolt.The small axial loads of composite excitation can restrain bolt failure,and the significant degree of this restraining effect is differ-ent for different preloads.Subsequently,a fracture analysis of the bolt was performed to verify the competitive failure relationship of the bolt from a microscopic perspective,and the competitive failure mechanism of the bolt was deter-mined.Based on the findings,we propose a calculation equation for the optimal preload of 8.8 grade high-strength bolts that can serve as a reference for engineering applications. 展开更多
关键词 BOLT PRELOAD loosening FATIGUE Competitive failure
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Potential contribution of pedicle screw design to loosening rate in patients with degenerative diseases of the lumbar spine:An observational study 被引量:1
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作者 Andrey Bokov Svetlana Pavlova +2 位作者 Anatoliy Bulkin Alexandr Aleynik Sergey Mlyavykh 《World Journal of Orthopedics》 2021年第5期310-319,共10页
BACKGROUND The majority of published data report the results of biomechanical tests of various design pedicle screw performance.The clinical relevance and relative contribution of screw design to instrumentation stabi... BACKGROUND The majority of published data report the results of biomechanical tests of various design pedicle screw performance.The clinical relevance and relative contribution of screw design to instrumentation stability have been insufficiently studied.AIM To estimate the contribution of screw design to rate of pedicle screw loosening in patients with degenerative diseases of the lumbar spine.METHODS This study is a prospective evaluation of 175 patients with degenerative diseases and instability of the lumbar spine segments.Participants underwent spinal instrumentation employing pedicle screws with posterior only or transforaminal interbody fusion.Follow-up was for 18 mo.Patients with signs of pedicle screw loosening on computed tomography were registered;logistic regression analysis was used to identify the factors that influenced the rate of loosening.RESULTS Parameters included in the analysis were screw geometry,type of thread,external and internal screw diameter and helical pitch,bone density in Hounsfield units,number of levels fused,instrumentation without anterior support,laminectomy,and unilateral and bilateral total facet joint resection.The rate of screw loosening decreased with the increment in outer diameter,decrease in core diameter and helical pitch.The rate of screw loosening correlated positively with the number of fused levels and decreasing bone density.Bilateral facet joint removal significantly favored pedicle screw loosening.The influence of other factors was insignificant.CONCLUSION Screw parameters had a significant impact on the loosening rate along with bone quality characteristics,the number of levels fused and the extensiveness of decompression.The significance of the influence of screw parameters was comparable to those of patient-and surgery-related factors.Pedicle screw loosening was influenced by helical pitch,inner and outer diameter,but screw geometry and thread type were insignificant factors. 展开更多
关键词 Degenerative diseases Lumbar spine Pedicle screw design Pedicle screw loosening
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Low-Cost Wireless Sensor Network Node Design for Multi-point Bolt Loosening Detection
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作者 徐云鹏 吴键 +1 位作者 商飞 何博侠 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI CSCD 2015年第3期318-324,共7页
Bolted connections are commonly used in aerospace structures.Once the bolts on the aircraft are damaged or loose,the consequence will be disastrous.Therefore,monitoring bolt loosening is especially required.However,pe... Bolted connections are commonly used in aerospace structures.Once the bolts on the aircraft are damaged or loose,the consequence will be disastrous.Therefore,monitoring bolt loosening is especially required.However,periodic manual inspection costs much money and time.And it is very difficult to achieve multi-point monitoring for many bolted structures in an aircraft.Therefore,a low-cost,reliable detection method based on wireless sensor networks is presented.The reed switch is selected as a sensor for bolt loosening monitor.The chip PT2262 and PT2272are chosen as hardware codec chip for multi-point placement.A wireless transmitter and receiver circuit is designed on 315 MHz frequency.The codec chip and the wireless transmission are triggered by the reed switches.Bolt loosening is detected by the receiving terminal and indicated by light and sound alarms.The wireless transmitter and the receiver circuit are tested and the monitoring system is verified by experiments.The results show that bolt loosening can be effectively detected within 300 m.The developed sensor network is expected to solve multi-point bolt detection problems and provide a low-cost and reliable monitoring technology. 展开更多
关键词 BOLT loosening multipoint monitoring WIRELESS sens
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LOOSENING AND LENGTHENING OF INTESTINAL TRACT AFTER RECTAL ISOLATION IN ANUS-SAVING RESECTION FOR RECTAL CARCINOMA
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作者 张保宁 余宏迢 邵永孚 《Chinese Journal of Cancer Research》 SCIE CAS CSCD 1995年第2期127-129,共3页
In low rectal cancer surgery,the section of rectum destal to the lower tumor maigin is relaxed and lengthened after fully isolation of the organ. This would facilitate the adoption of anus saving operation.Before and ... In low rectal cancer surgery,the section of rectum destal to the lower tumor maigin is relaxed and lengthened after fully isolation of the organ. This would facilitate the adoption of anus saving operation.Before and after fully isolation of the rectum in low ratal cancer surgery, the distance between the lower tumor margin and the anorectal line was measured by the same rectuscope introduced through the anus.The two results were compared .The average lengthening was less than 1 cm if the lower tumor marginanorectal line distance was 5 cm.It was 1─2 cm if the lower tumor margin-anorectal distance was 6 cm.It was more than 2 cm if the distance was 7─9 cm.The loosening and lengthening of the rectal canal was related to the presence of lymphnode metastasis and the skill of the operator.The lengthening was also influenced by the body build of the patient,involvement of the rectal circumference and the Dukes stage. Modified Park's operation,trans abdominosacral resection with anastormosis of rectum,and anterior resection on transpubic approach are indicated for those in whom the lower tumor margin-anorectal line distance was 5 cm The rectectomy-anastomosis in the abdominal cavity(Dixon's operation)is indicated for those in whom the lower tumor margin-anorectal line was 6 cm.If manual anastomosis is difficult,stapling device may be used. The anus saving resection is easy if the distance was 7─9 cm. 展开更多
关键词 Rectal carcinoma Lateral ligament Isolation of rectum loosening and lengthening of intestinal tract Anus-saving resection.
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Metallosis with spinal implant loosening after spinal instrumentation:A case report
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作者 Yiu Hin Kwan Hong Lee Terry Teo +1 位作者 Shree Kumar Dinesh Wee Lim Loo 《World Journal of Orthopedics》 2023年第8期651-661,共11页
BACKGROUND Spinal metallosis is a rare complication following spinal instrumentation whereby an inflammatory response to the metal implants results in the development of granulomatous tissue.CASE SUMMARY We describe t... BACKGROUND Spinal metallosis is a rare complication following spinal instrumentation whereby an inflammatory response to the metal implants results in the development of granulomatous tissue.CASE SUMMARY We describe the case of a 78-year-old woman who had recurrence of back pain 5 years after lumbar spine posterior decompression and instrumented fusion.Lumbar spine radiographs showed hardware loosening and magnetic resonance imaging showed adjacent segment disease.Revision surgery revealed evidence of metallosis intraoperatively.CONCLUSION Spinal metallosis can present several years after instrumentation.Radiography and computed tomography may demonstrate hardware loosening secondary to metallosis.Blood metal concentrations associated with spinal metallosis have yet to be established.Hence,metallosis is still an intraoperative and histopathological diagnosis.The presence of metallosis after spinal instrumentation likely indicates a more complex underlying problem:Pseudarthrosis,failure to address sagittal balance,infection,and cross-threading of set screws.Hence,identifying metallosis is important,but initiating treatment promptly for symptomatic implant loosening is of greater paramount. 展开更多
关键词 METALLOSIS SPINE INSTRUMENTATION Implant loosening CORROSION Case report
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IL-1B,IL-6 and TNF-a change of experimental knee joint degeneration model and effect of local loosening therapy
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作者 ZHANG Ying ZHOU Jiang-nan +2 位作者 LI Jia-bang ZHOU Jing-cai ZHOU Zhong-huan 《Journal of Central South University of Technology》 2005年第z1期356-358,共3页
Objective To observe IL-1B,IL-6 and TNF-a level change of the joint fluid in the experimental knee joint degeneration and the effect of the local loosening therapy.Methods Thirty rabbits were divided into 3 groups at ... Objective To observe IL-1B,IL-6 and TNF-a level change of the joint fluid in the experimental knee joint degeneration and the effect of the local loosening therapy.Methods Thirty rabbits were divided into 3 groups at random:ten in the normal contrast group,ten in the blank model group and ten in the loosening therapy group to observe the IL-1B,IL-6 and TNF-a change of the joint fluid before and after the treatment in each group.Result IL-1B,IL-6 and TNF-a level in the blank model group was obviously higher than that in the normal group.(P<0.05).IL-1B,IL-6 and TNF-a level in the treatment group was obviously lower than that in the normal group.(P<0.05).Conclusions 1)IL-1B,IL-6 and TNF-a level of the joint fluid in the blank model group was obviously higher than that in the normal group.2)Loosening soft tissues of the knees can improve IL-1B,IL-6 and TNF-a level of the joint fluid. 展开更多
关键词 experimental knee joint degeneration local loosening therapy
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利格列汀调控巨噬细胞极化和破骨细胞形成缓解磨损颗粒诱导的骨质溶解
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作者 杨鹏 张巍 +4 位作者 李文明 李文豪 吴泽彬 周军 耿德春 《中国组织工程研究》 CAS 北大核心 2025年第12期2421-2428,共8页
背景:研究发现,在利格列汀的干预下,巨噬细胞更多的由M1转向M2极化,降低了相关炎性因子的释放,缓解了局部炎症。目的:探讨利格列汀对巨噬细胞极化、破骨细胞活化及磨损颗粒诱导炎性骨溶解的影响。方法:(1)细胞实验:①巨噬细胞极化:将RAW... 背景:研究发现,在利格列汀的干预下,巨噬细胞更多的由M1转向M2极化,降低了相关炎性因子的释放,缓解了局部炎症。目的:探讨利格列汀对巨噬细胞极化、破骨细胞活化及磨损颗粒诱导炎性骨溶解的影响。方法:(1)细胞实验:①巨噬细胞极化:将RAW264.7细胞分4组培养,对照组细胞加入高糖培养基;M1诱导组加入M1诱导培养基(含脂多糖100 ng/mL和干扰素γ20 ng/mL的高糖培养基)模拟炎症环境;利格列汀低、高剂量组分别加入50,200 nmol/L利格列汀处理4 h后加入M1诱导培养基。巨噬细胞极化诱导24 h后,分别进行巨噬细胞极化免疫荧光染色和RT-PCR检测。②破骨细胞活化:将RAW264.7细胞分为4组培养,对照组使用高糖培养基培养,破骨细胞诱导组、利格列汀低剂量组及高剂量组进行破骨细胞诱导,待微小破骨细胞成形后,用利格列汀(50,200 nmol/L)分别干预细胞3 d,进行细胞抗酒石酸酸性磷酸酶染色和RT-PCR检测。(2)动物实验:将24只雄性C57BL/6J小鼠随机分为4组,即假手术组、模型组、利格列汀低剂量组及高剂量组,后3组通过将钛颗粒悬浊液注射至颅骨表面建立颅骨骨溶解模型,从造模后第2天开始,利格列汀低、高剂量组分别灌胃利格列汀(2,10 mg/kg),每天1次,造模3周后,检测血清巨噬细胞极化标志蛋白及炎性因子水平,收集颅骨进行micro-CT扫描、骨参数分析及苏木精-伊红染色评估骨溶解及形态学变化。结果与结论:①细胞实验:与M1诱导组比较,利格列汀低、高剂量组可显著抑制巨噬细胞的M1极化、促进M2极化(P<0.01),且以高剂量组效果更显著(P<0.01)。与破骨诱导组比较,利格列汀低、高剂量组可抑制破骨细胞的活化及骨质吸收,且以高剂量组抑制更显著。与对照组比较,M1诱导组炎性因子mRNA表达升高(P<0.01),而与M1诱导组相比较,利格列汀低、高剂量组炎性因子mRNA表达显著降低(P<0.01)。与对照组比较,破骨诱导组破骨功能标志物的mRNA表达升高(P<0.01);与破骨诱导组比较,利格列汀低、高剂量组破骨功能标志物的mRNA表达降低(P<0.01),且以高剂量组降低更明显。②动物实验:钛颗粒植入导致小鼠颅骨骨溶解破坏,利格列汀可抑制钛颗粒诱导的骨溶解,其中以高剂量组抑制作用更显著。结果表明利格列汀具有调节巨噬细胞极化、抑制破骨细胞活化及对骨骼系统的保护作用。 展开更多
关键词 利格列汀 巨噬细胞极化 破骨细胞活化 磨损颗粒 无菌性假体松动 假体周围骨溶解
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Orbital-abrasion-assisted Electroforming of Non-rotating Parts 被引量:5
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作者 李学磊 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2011年第5期827-831,共5页
A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles a... A novel technique of electroforming with orbital moving cathode was carried out for the fabrication of non-rotating thin-walled parts.This technique features a large number of insulating and insoluble hard particles as a real-time polishing to the cathode.When cathode moves,hard particles polish its surface and provide the nickel non-rotating parts with near-mirror finishing.Morphology,microstructure,surface roughness and micro hardness of deposits fabricated by novel method were studied in contrast with the sample produced by traditional electroforming methods.Theoretical analysis and experimental results showed that the novel technique could effectively remove the hydrogen bubbles and nodules,disturb the crystal nucleation,and refine the grains of layer.The mechanical properties were significantly improved over traditional method.The micro-hardness of the layer was in a uniform distribution ranging from 345 HV to 360 HV.It was confirmed that this technique had practical significance to non-rotating thin-walled parts. 展开更多
关键词 ELECTROFORMING orbital cathode ABRASION non-rotating parts
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茶园仿生往复式开沟松土机设计与试验 被引量:1
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作者 秦宽 郎旭涛 +6 位作者 沈周高 吴正敏 毕海军 曹成茂 孙燕 葛俊 方梁菲 《农业机械学报》 EI CAS CSCD 北大核心 2024年第3期29-39,共11页
丘陵山区茶园土壤板结、石砾较多,使用传统旋转或移动式开沟机会出现打石跳刀、刀具无法入土、开沟不深、作业阻力大的问题。为此,依据人工铲土具有自发性以最低功耗完成最优作业路径的特点,设计仿人工铲土动作的曲柄摇杆式开沟装置,并... 丘陵山区茶园土壤板结、石砾较多,使用传统旋转或移动式开沟机会出现打石跳刀、刀具无法入土、开沟不深、作业阻力大的问题。为此,依据人工铲土具有自发性以最低功耗完成最优作业路径的特点,设计仿人工铲土动作的曲柄摇杆式开沟装置,并研制小型茶园往复式开沟松土机。通过分析人工使用铁锹铲土的动作,建立入土、切土、抛土的运动模型,基于Matlab软件分析得到人工铲土时铁锹锹尖运动轨迹的拟合方程,以此方程为基准,建立曲柄连杆机构的目标函数,结合约束条件解出曲柄摇杆机构结构参数,同时对开沟铲进行开沟阻力分析,确定开沟铲的结构参数。建立Recurdyn和EDEM耦合的开沟铲-土壤互作仿真模型,并进行三因素三水平正交试验,对作业和结构参数进行优化,得到最优参数组合:机器前进速度v为0.06 m/s、曲柄转速n为42 r/min、入土倾角φ为80°。田间试验结果表明,茶园往复式开沟松土机作业平均开沟深度为211.5 mm,开沟功率为0.119 kW,沟深稳定性系数为90.9%,相较于传统旋转式开沟机,开沟功率降低6.3%,沟深稳定性系数提高3.1个百分点,整机作业质量满足茶园农艺要求。 展开更多
关键词 茶园 开沟松土机 仿生 曲柄连杆机构 RECURDYN EDEM
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深松铲对砖红壤扰动行为影响的仿真与试验 被引量:2
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作者 王彬 张喜瑞 《农机化研究》 北大核心 2024年第6期157-161,共5页
针对香蕉地深松作业相关研究较少,深松铲-土壤耦合机理尚未明确等问题,结合海南热区香蕉地砖红壤土的物理特性,利用离散元虚拟仿真试验,堆积生成了耕作层、犁底层和心土层3层土壤模型,建立了滑切深松铲-土壤耕作模型,并通过对比虚拟仿... 针对香蕉地深松作业相关研究较少,深松铲-土壤耦合机理尚未明确等问题,结合海南热区香蕉地砖红壤土的物理特性,利用离散元虚拟仿真试验,堆积生成了耕作层、犁底层和心土层3层土壤模型,建立了滑切深松铲-土壤耕作模型,并通过对比虚拟仿真试验,研究了滑式深松铲和国标深松铲对海南香蕉地土壤的扰动情况。结果表明:在相同的作业条件下,滑式深松铲作用下的土壤颗粒在x、y和z方向的最大运动速度均明显大于国标深松铲对土壤颗粒的作用,且滑式深松铲的扰动轮廓要明显大于国标深松铲作业的扰动轮廓,同时滑式深松铲作用下土壤蓬松度和土壤扰动系数均大于国标深松铲作用产生的深松效果,进一步验证了所设计的滑式深松铲更适用于海南香蕉地的深松作业。 展开更多
关键词 滑式深松铲 土壤扰动 深松 离散元法
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Should the Harsh Penalties on Drunk Driving Be loosened?
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《ChinAfrica》 2017年第7期12-13,共2页
Recently,reform on charges against dangerous driving has stirred up debate among the public.A new stipulation by China’s Supreme People’s court which took effect on May 1 granted judges the discretion to decide whet... Recently,reform on charges against dangerous driving has stirred up debate among the public.A new stipulation by China’s Supreme People’s court which took effect on May 1 granted judges the discretion to decide whether someone caught driving under the influence of alcohol should be held criminal responsible by taking into account how drunk the person is,road conditions and the seriousness of damages. 展开更多
关键词 In Should the Harsh Penalties on Drunk Driving Be loosened BE
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同轴脉冲形成线振动环境适应性优化设计
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作者 范红艳 潘亚峰 +4 位作者 王俊杰 侯振园 孙旭 樊旭亮 郭旭 《强激光与粒子束》 CAS CSCD 北大核心 2024年第1期70-75,共6页
以带有悬臂结构的同轴脉冲形成线为研究对象,开展提高振动环境适应性的优化设计。首先,通过实际工况分析及仿真计算,确定形成线内筒的盲孔螺钉可采用的防松措施有:使用施必劳螺纹并涂抹防松胶;优化螺钉数量。其次,通过仿真分析和绝缘试... 以带有悬臂结构的同轴脉冲形成线为研究对象,开展提高振动环境适应性的优化设计。首先,通过实际工况分析及仿真计算,确定形成线内筒的盲孔螺钉可采用的防松措施有:使用施必劳螺纹并涂抹防松胶;优化螺钉数量。其次,通过仿真分析和绝缘试验,优化尾端绝缘子材料,提高悬臂支撑的中内筒连接刚度。最后,开展振动试验考核,优化后的形成线等效件可以通过长时间的振动考核,相比优化前的振动环境适应性有很大提高,验证了优化设计的有效性。该研究结果对同类型脉冲功率源的振动环境适应性设计具有参考意义。 展开更多
关键词 同轴脉冲形成线 振动环境适应性 螺钉防松 绝缘试验 优化设计
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冷凉区黑土有机质和玉米产量双提升技术探索及经济效益分析
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作者 徐超 侯瑞星 +5 位作者 杨克军 付健 王宇先 孙淑楠 苗宇 齐翔琨 《干旱地区农业研究》 CSCD 北大核心 2024年第2期121-130,共10页
为明确有机肥还田+保护性耕作措施下黑龙江省西部土壤有机质和作物产量的双提升技术效果,2021年10月,在黑龙江省西部齐齐哈尔市梅里斯区开展试验,以玉米为供试作物,设置5个处理:有机肥+深松40 cm(YS40)、秸秆留茬+深松40 cm(WS40)、有机... 为明确有机肥还田+保护性耕作措施下黑龙江省西部土壤有机质和作物产量的双提升技术效果,2021年10月,在黑龙江省西部齐齐哈尔市梅里斯区开展试验,以玉米为供试作物,设置5个处理:有机肥+深松40 cm(YS40)、秸秆留茬+深松40 cm(WS40)、有机肥+旋耕20 cm(YS20)、秸秆留茬+旋耕20 cm(WS20)、有机肥表施+免耕(YB);一个对照:秸秆留茬+免耕(CK)。结果表明:施入有机肥的处理能够提升深土层土壤肥力,在20~40 cm土层中YS20处理与CK处理相比有机质和全氮依次提升11.56 g·kg^(-1)和0.57 g·kg^(-1);40~60 cm土层中YS40处理与CK处理相比有机质和全氮依次提升2.83 g·kg^(-1)和0.28 g·kg^(-1)。土壤结构方面,在0~20 cm土层中YB处理的容重较CK降低17.5%、含水量提升35.5%,40~60 cm土层中YS40处理的容重较CK处理降低5.3%、含水量提升38.4%。有机肥与保护性耕作处理提高了玉米不同生育时期叶面积指数、叶绿素含量和干物质积累量,进而提高了玉米产量,第二年的YS40、YS20、YB处理较CK处理分别增产14.5%、18.5%、11.4%。收益分析表明,与CK处理相比,2021年YB处理和2022年YS20处理收益增加最多,分别增加5770元·hm^(-2)和5223元·hm^(-2)。综上所述,黑龙江省西部薄层黑土实施有机肥还田+保护性耕作是提升土壤有机质、有机碳储量、全氮、全氮储量、玉米产量和经济效益的有效措施。 展开更多
关键词 冷凉区黑土 有机肥深施深松 玉米产量 经济效益 土壤培肥
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考虑松动圈影响的公路隧道大直径竖井围岩压力计算方法
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作者 任兆丹 冀成 +3 位作者 史育峰 邱军领 邹祯祥 赖金星 《科学技术与工程》 北大核心 2024年第15期6448-6458,共11页
为研究公路隧道大直径竖井围岩压力计算方法,基于极限平衡法推导,并与官田竖井实测数据进行了对比验证,最后分析了竖井直径、侧压力系数、围岩等级对竖井围岩压力的影响规律。结果表明:①与实测数据对比结果显示,本文公式的平均误差度在... 为研究公路隧道大直径竖井围岩压力计算方法,基于极限平衡法推导,并与官田竖井实测数据进行了对比验证,最后分析了竖井直径、侧压力系数、围岩等级对竖井围岩压力的影响规律。结果表明:①与实测数据对比结果显示,本文公式的平均误差度在12.85以内,相比其他公式的误差度在180以上,使相对误差减小了167.15以上,可指导工程人员进行竖井的施工设计;②竖井开挖直径越大,竖井井壁围岩压力越大,但是围岩压力的增长幅度随直径增大而逐渐减弱;③在未达到极限深度之前,侧压力系数越大,竖井井壁围岩压力越大;达到极限深度以后,不同侧压力系数下井壁的围岩压力一样大。侧压力系数越大,井壁围岩压力随竖井深度的增长越大,更快达到最大井壁围岩压力,即极限深度越小;④围岩等级越高,竖井的井壁围岩压力越小,在达到极限深度之后的围岩压力也越小。 展开更多
关键词 围岩压力 公路隧道 大直径竖井 松动圈
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接触网用精准力矩控制防松技术创优研究
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作者 王玉环 《铁道工程学报》 EI CSCD 北大核心 2024年第10期63-69,共7页
研究目的:轨道交通的发展程度已成为现代化的标志,对国家经济发展、社会稳定均起着关键性作用,其中牵引供电系统的安全可靠性逐渐成为民众关注的焦点。供电系统中,接触网与受电弓的良好动态匹配是实现机车平稳取流的关键,但频繁的交变... 研究目的:轨道交通的发展程度已成为现代化的标志,对国家经济发展、社会稳定均起着关键性作用,其中牵引供电系统的安全可靠性逐渐成为民众关注的焦点。供电系统中,接触网与受电弓的良好动态匹配是实现机车平稳取流的关键,但频繁的交变接触力作用引起的高频振动,会导致接触网零部件的松动,特别是在高速铁路运行过程中,列车机械振动与风振耦合,更加剧了螺纹松动。因此设备及零部件的防松是安全可靠最基本的要求。本文旨在对接触网结构、装备及零件间的连接方式、螺纹连接失效模式及基体压溃现象等进行综合能力分析。采用定性调查法、定量试验法、理论计算及有限元定型对比模拟计算等手段,对螺纹的紧固与防松技术性能进行对比分析及防松能力评价,并提出简单、长效、可控的螺纹连接的新型技术。研究结论:(1)接触网用的碳钢或添加元素的碳钢M16及以上规格的螺栓、螺母占比约为40%,但是紧固力矩控制及防松性能评价往往被忽略;(2)倒锥体的锚栓一定要在精确的紧固力矩下使得胶与本体脱离产生膨胀挤压才可更好地发挥作用,因此紧固力矩的精确控制就是重要的安全指标;(3)通过对松开力矩及紧固力矩关系论证得知,并非松开力矩只要大于紧固力矩就可完全防松,如果处理不当会造成螺纹黏着及咬死现象,紧固力矩精准控制才是真正防松的关键;(4)精准力矩控制型防松螺母,能以最简单的操作达到最精确的力矩值,保证可靠连接、指标可控、节能增效,更适用于高原高海拔高空作业;(5)本研究成果可应用于接触网设备、构筑物及零部件的螺栓紧固及防松。 展开更多
关键词 轨道交通 接触网 螺纹连接 防松螺母
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螺栓连接和拉铆连接在剪切循环荷载作用下的松动行为研究
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作者 杨俊芬 郝凯丽 +3 位作者 钟炜辉 王维新 苗广威 张钦 《建筑钢结构进展》 CSCD 北大核心 2024年第3期52-61,共10页
拉铆连接凭借其优秀的防松性能,被应用于越来越多的工程领域。为研究国产新型拉铆钉在剪切循环荷载作用下的松动性能,以应用最为广泛的螺栓连接为对照,分别对规格为8 mm的4.8级普通螺栓、4.8级防松螺栓以及小规格拉铆钉进行剪切循环荷... 拉铆连接凭借其优秀的防松性能,被应用于越来越多的工程领域。为研究国产新型拉铆钉在剪切循环荷载作用下的松动性能,以应用最为广泛的螺栓连接为对照,分别对规格为8 mm的4.8级普通螺栓、4.8级防松螺栓以及小规格拉铆钉进行剪切循环荷载下的松动试验研究,分析了三类连接在剪切循环荷载作用下的松动过程,研究了荷载幅值和频率对螺栓连接和拉铆连接松动行为的影响。结合微观测试手段分析其损伤形貌,进一步研究剪切循环荷载下螺栓和拉铆钉的防松原理及微动损伤机制。研究表明:在同种工况下拉铆连接的防松性能优于螺栓连接的防松性能;当荷载幅值增大或荷载频率减小时,螺栓连接和拉铆连接的松动程度增大;相较于螺栓,拉铆钉独特的圆弧结构牙型和铆接成型后牙型配合面的过盈配合机制,使其防松性能有明显提升;螺栓与拉铆钉的磨损机制主要是磨粒磨损和疲劳磨损。 展开更多
关键词 拉铆连接 螺栓连接 防松性能 剪切循环荷载 磨粒磨损 疲劳磨损
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Mulligan动态关节松动术结合中药熏蒸、牵伸疗法治疗肩周炎的临床观察
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作者 龚星星 温振宇 +1 位作者 张军辉 曾丽玲 《中国医学创新》 CAS 2024年第26期5-9,共5页
目的:分析Mulligan动态关节松动术结合中药熏蒸、牵伸疗法治疗肩周炎的临床效果。方法:选取2021年4月—2023年5月新余钢铁集团有限公司中心医院康复医学科收治的90例肩周炎患者,按随机数字表法分成三组,各30例。对照组给予中药熏蒸和牵... 目的:分析Mulligan动态关节松动术结合中药熏蒸、牵伸疗法治疗肩周炎的临床效果。方法:选取2021年4月—2023年5月新余钢铁集团有限公司中心医院康复医学科收治的90例肩周炎患者,按随机数字表法分成三组,各30例。对照组给予中药熏蒸和牵伸疗法,A组在对照组基础上实施Mulligan动态关节松动术,B组在对照组基础上实施Maitland关节松动术。比较三组疼痛强度、日常生活活动能力、肩关节活动范围和功能。结果:治疗2周后,三组Barthel指数(BI)评分和外展、前屈、内旋、后伸活动度及Constant-Murley肩关节评分从高到低依次为A组、B组、对照组,整体疼痛评估量表(GPS)评分从低到高依次为A组、B组、对照组,差异均有统计学意义(P<0.05)。结论:Mulligan动态关节松动术结合中药熏蒸、牵伸疗法可以改善肩关节活动范围,有效缓解肩关节疼痛,促进肩关节功能恢复,改善患者日常生活水平。 展开更多
关键词 Mulligan动态关节松动术 Maitland关节松动术 中药熏蒸 牵伸疗法 肩周炎
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