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基于drop-off ddPCR方法检测急性髓系白血病C-KIT基因N822位点突变及其临床应用
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作者 李婷 金晔 +7 位作者 袁倩 姚冬明 向鹤麟 肖高飞 于迪 冷加燕 林江 钱军 《江苏大学学报(医学版)》 CAS 2024年第2期151-155,160,共6页
目的:建立急性髓系白血病(acute myeloid leukemia, AML)患者C-KIT基因N822位点突变的drop-off微滴式数字PCR(droplet digital PCR,ddPCR)定量检测方法,并评价其临床应用价值。方法:针对C-KIT基因第17外显子设计一对引物及探针,优化drop... 目的:建立急性髓系白血病(acute myeloid leukemia, AML)患者C-KIT基因N822位点突变的drop-off微滴式数字PCR(droplet digital PCR,ddPCR)定量检测方法,并评价其临床应用价值。方法:针对C-KIT基因第17外显子设计一对引物及探针,优化drop-off ddPCR反应条件及体系,评价该方法的特异性、灵敏度、重复性,使用所建立的方法对140例已行Sanger测序的AML初诊患者骨髓标本进行检测,并用二代测序(next generation sequencing, NGS)验证结果;用drop-off ddPCR对3例阳性患者化疗后C-KIT突变频率进行动态监测。结果:drop-off ddPCR检测C-KIT基因N822位点突变的最适退火温度为54℃,空白检测限为1.62拷贝数/μL,最低检测下限为10.12拷贝数/μL,线性良好。140例AML初诊患者样本中Sanger测序检出2例阳性(1.4%),而ddPCR共检出突变7例(5.0%),突变频率为0.29%~7.41%;进一步应用常规NGS方法对ddPCR阳性样本进行验证,共检出阳性3例(2.1%),等位基因频率为1.26%~8.00%。动态监测3例阳性患者C-KIT突变频率,结果显示治疗达完全缓解时C-KIT突变频率明显下降甚至降低至0。结论:本研究建立了检测C-KIT基因N822位点突变的drop-off ddPCR技术,具有良好的方法学检测性能,其灵敏度高于Sanger测序和NGS,有望用于阳性患者缓解后的可检测残留疾病监测及治疗指导。 展开更多
关键词 drop-off微滴式数字PCR C-KIT基因 基因突变 微小残留病 急性髓系白血病 预后
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人工法off-line HDF对血液透析充分性和高同型半胱氨酸血症的影响
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作者 吴飞飞 罗来敏 +2 位作者 范燕娜 张桂玲 龚燕燕 《实用临床医学(江西)》 CAS 2024年第4期19-22,27,共5页
目的探究人工法off-line HDF对维持性血液透析(MHD)患者透析充分性、高同型半胱氨酸血症(HHcy)的影响。方法随机选取2021至2023年于南昌大学第一附属高新医院血液透析中心稳定透析6个月以上的MHD患者30例,进行单中心自身对照研究,时长6... 目的探究人工法off-line HDF对维持性血液透析(MHD)患者透析充分性、高同型半胱氨酸血症(HHcy)的影响。方法随机选取2021至2023年于南昌大学第一附属高新医院血液透析中心稳定透析6个月以上的MHD患者30例,进行单中心自身对照研究,时长6个月。前3个月维持每周2次高通量血液透析(HFHD)联合1次on-line HDF,后3个月维持每周2次人工法off-line HDF联合1次on-line HDF。于研究第3个月、第6个月时用全自动生化分析仪检测透析前后血尿素氮(BUN)、血肌酐(SCr)、β2-微球蛋白(β2MG)、同型半胱氨酸(Hcy)、白蛋白(Alb)、C反应蛋白(CRP)、血红蛋白(Hb)、甲状旁腺素(iPTH)、磷(P)、钾(K)水平;计算血清尿素清除指数(Kt/V)、尿素下降率(URR)和β2MG清除率。结果人工法off-line HDF模式透析的Kt/V、URR及β2MG清除率均较显著高于HFHD模式透析(P<0.05);人工法off-lineHDF模式透析Kt/V、URR及β2MG清除率达到透析充分的百分率分别为83.33%、83.33%和93.33%,均显著高于HFHD模式透析(P<0.05)。与HFHD模式透析时相比,人工法off-lineHDF模式透析结束后,患者透析前Hcy水平降低,Alb水平升高(P<0.05)。结论人工法off-line HDF模式透析可显著增加Kt/V、URR和β2MG清除率,提高MHD患者的透析充分性达标率,且对HHcy具有改善作用。 展开更多
关键词 人工法off-line HDF 血液透析 透析充分性 高同型半胱氨酸血症 血液透析滤过
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分离膜的Trade-off效应及其突破研究进展
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作者 杨誉名 贾子钰 杨春维 《应用化工》 CAS CSCD 北大核心 2024年第6期1466-1468,共3页
综述通过文献调研,对膜材料在水通量与污染物截留效率之间存在的此消彼长的Trade-off效应进行分析,并对近几年国内外突破分离膜Trade-off效应的方法进行了总结。结果表明,膜表面接枝两性离子技术、非溶剂诱导相分离技术、结构改性技术... 综述通过文献调研,对膜材料在水通量与污染物截留效率之间存在的此消彼长的Trade-off效应进行分析,并对近几年国内外突破分离膜Trade-off效应的方法进行了总结。结果表明,膜表面接枝两性离子技术、非溶剂诱导相分离技术、结构改性技术、物理共混技术、表面涂覆技术等可以突破该技术瓶颈。而物理共混技术表现出非常优异的效果,且该技术方法相对简便,无需更新设备,易于实施,制备出的膜材料具有良好的机械性能和产水能力。综述为高效分离膜的开发提供了新的技术思路,为膜技术的应用和推广提供有益的技术借鉴。 展开更多
关键词 Trade-off规律 膜材料 表面接枝法 表面涂覆法 掺杂法
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Validation of the TOPAS Monte-Carlo Code of the Off-Field Dose of a 6 MV Synergy Linac
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作者 Kodjo Joel Fabrice N’Guessan Ibrahima Sakho Bogbé D. L. H. Gogon 《Journal of Biosciences and Medicines》 2024年第7期38-54,共17页
The risk of radiation-induced second cancer and the late tissue loss due to Off-field doses in radiotherapy remain a serious concern. Monte Carlo (MC) simulation is currently one of the most accurate methods for calcu... The risk of radiation-induced second cancer and the late tissue loss due to Off-field doses in radiotherapy remain a serious concern. Monte Carlo (MC) simulation is currently one of the most accurate methods for calculating these doses. MC simulation model based on the Particle Simulation Tool (TOPAS) has been developed to simulate the off-field dose of an Elekta Synergy linear accelerator (Linac) emitting 6 MV photons. Measurements were taken in a water phantom using an ionization chamber to validate this model. The Percentage Depth Dose (PDD) at the depth of 0.0, 5.0, 10.0 and 15.0 cm from the beam axis for a 10 × 10 cm2 field size was measured and simulated. Off-field dose profiles at the depth of 1.5 (dmax), 5.0 and 10.0 cm for field sizes of 5 × 5, 10 × 10, 15 × 15, and 20 × 20 cm2 respectively were measured and simulated. Comparison of measured and simulated off-field dose values showed a good agreement. The average gamma passing rate of the PDDs and profiles curves for off-field doses were 87.5% and 98.11% respectively. The local dose difference based on the PDD curve between the measured and simulated was less than 6.0 % for all locations. For all field size considered in this study, the average difference between profile curves for off-field dose measured and simulated was 9.1%. PDDs and Profiles curves for off-field dose simulation uncertainties were less than 2.0% and 1.0% respectively. TOPAS-MC simulation model developed is a good representation of our 6 MV Linac Elekta Synergy for assessing off-field dose, which would be the primary cause of some secondary cancers. 展开更多
关键词 Radiotherapy off-Field Dose Secondary Cancer TOPAS-MC Simulation DOSIMETRY
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Basic Research on the Burden of Dropping off and Picking up Children: Differences by Employment Type and Gender in the Tokyo Metropolitan Area
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作者 Jun Morio Koshi Isono +1 位作者 Masahiko Kikuchi Tetsuo Morita 《Journal of Transportation Technologies》 2024年第3期445-461,共17页
There is a need to reduce the burden of child drop-off and pick-up for child-rearing generations, but most studies on the actual situation in Japan are based on survey results. In this study, we analyzed differences i... There is a need to reduce the burden of child drop-off and pick-up for child-rearing generations, but most studies on the actual situation in Japan are based on survey results. In this study, we analyzed differences in child drop-off and pick-up by employment type and gender, utilizing the “Metropolitan Area Person Trip Survey,” which is a statistical data set. The study targeted households in which both spouses were between 30 and 49 years old, had children under the age of 6, and included the following three groups. 1) Dual-income Group 1 (both spouses employed/on contract/temporary);2) Dual-income Group 2 (husband employed/on contract/temporary, wife part-time);3) Full-time housewife group (husband employed, wife unemployed). The analysis revealed that a) wives are almost always responsible for dropping off and picking up their children;b) husbands drop off and pick up their children less frequently in dual-income households;and c) households with children raising within 10 to 30 km of Tokyo Station have longer commuting times and need to reduce the burden of dropping off and picking up their children. 展开更多
关键词 Drop-off and Pick-Up Employment Type GENDER Dual-Income Households Tokyo Metropolitan Area
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Preoperative Serum Albumin Levels and Postoperative Acute Kidney Injury in Off-Pump Coronary Artery Bypass Surgery: A Single-Center Study in Bangladesh
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作者 Ahmad Pear Salahuddin Md. Abir Tazim Chowdhury +6 位作者 Munama Magdum Dewan Iftakher Reza Chowdhury Nittya Nanda Pal Md. Nahedul Morshed Md. Zafar-Al-Nimari Latifa Nasrin Farooque Ahmed 《World Journal of Cardiovascular Surgery》 2024年第8期131-144,共14页
Background: Serum albumin, a vital plasma protein, helps maintain intravascular colloidal osmotic pressure, cardiac output, and renal function. Low preoperative serum albumin is linked to poor outcomes, including acut... Background: Serum albumin, a vital plasma protein, helps maintain intravascular colloidal osmotic pressure, cardiac output, and renal function. Low preoperative serum albumin is linked to poor outcomes, including acute kidney injury (AKI), after off-pump coronary artery bypass (OPCAB) surgery. This study aimed to assess the relationship between preoperative serum albumin levels and early postoperative renal injury. Methods: This prospective comparative cross-sectional study was conducted from August 2019 to February 2021 at the National Heart Foundation Hospital & Research Institute, Bangladesh. It included 160 adult patients with normal preoperative renal function undergoing OPCAB. Patients were divided into two groups: Group A (serum albumin ≥ 4.0 gm/dl) and Group B (serum albumin Results: Preoperative serum albumin was significantly different between groups (Group A: 4.21 ± 0.05 gm/dl, Group B: 3.69 ± 0.04 gm/dl, p = 0.028). Group B had a higher incidence of hypertension (71.25% vs. 51.25%, p st and 3rd postoperative days were higher in Group B (p th day. Postoperative AKI occurred in 18.75% of Group A and 36.25% of Group B. Multivariate regression indicated that low preoperative serum albumin is an independent risk factor for postoperative AKI (p = 0.012, OR = 1.815, CI: 0.675 - 1.162). Conclusion: Preoperative serum albumin level is a valuable predictor of postoperative renal function. Ensuring high normal serum albumin levels before surgery can help minimize the risk of postoperative AKI. 展开更多
关键词 Serum Albumin Acute Kidney Injury (AKI) off-Pump Coronary Artery Bypass Surgery BANGLADESH
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Off-Pump Coronary Artery Bypass Grafting in Patients with Left Ventricular Dysfunction: Short-Term Results from a Single Center in Bangladesh
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作者 Muhit Abdullah Md. Abir Tazim Chowdhury +9 位作者 Satyajit Sharma Rehana Akther Munama Magdum Munjerin Refat Synthee Md. Zafar-Al-Nimari Saikat Das Gupta Saleh Ahmed Samir Kumar Biswas M. Quamrul Islam Talukder Farooque Ahmed 《World Journal of Cardiovascular Surgery》 2024年第9期145-156,共12页
Background: Off-pump coronary artery bypass grafting (OPCAB) is considered a safer alternative to on-pump surgery, especially in patients with left ventricular dysfunction (LVD). Objectives: This study assessed short-... Background: Off-pump coronary artery bypass grafting (OPCAB) is considered a safer alternative to on-pump surgery, especially in patients with left ventricular dysfunction (LVD). Objectives: This study assessed short-term outcomes and functional improvements in LVD patients post-OPCAB. Methods: The study included 200 coronary artery disease patients who underwent isolated off-pump coronary artery bypass grafting (OPCAB) at the National Heart Foundation Hospital and Research Institute between January 2019 and June 2020. Patients were categorized into Group 1, with a left ventricular ejection fraction (LVEF) of 30% - 39%, and Group 2, with an LVEF of 40% or higher. Echocardiographic assessments of left ventricular dimensions and ejection fraction were performed preoperatively, at discharge, and one month postoperatively. Results: In Group 1, preoperative left ventricular internal dimensions during diastole (LVIDd) and systole (LVIDs) were 53.48 ± 4.40 mm and 44.23 ± 3.93 mm, respectively, with a left ventricular ejection fraction (LVEF) of 35.28% ± 2.26%. At discharge, these values improved to 51.58 ± 4.04 mm (LVIDd), 41.23 ± 5.30 mm (LVIDs), and 39.25% ± 3.75% (LVEF). One month postoperatively, further improvements were observed: 46.29 ± 3.76 mm (LVIDd), 37.45 ± 3.68 mm (LVIDs), and 43.22% ± 4.67% (LVEF). Group 2 showed similar positive outcomes, with preoperative values of 47.09 ± 5.06 mm (LVIDd), 35.11 ± 5.25 mm (LVIDs), and 50.13% ± 7.25% (LVEF), improving to 42.37 ± 4.18 mm (LVIDd), 31.05 ± 4.19 mm (LVIDs), and 55.33% ± 7.05% (LVEF) at one month postoperatively. Both groups demonstrated significant improvements in left ventricular function and NYHA class, with most patients moving from class III/IV to I/II. Complications were minimal, and no mortality was observed. Conclusion: OPCAB is safe and effective for patients with LVEF 30% - 39% and LVEF ≥ 40%, providing significant short-term functional improvements without increased risk. 展开更多
关键词 off-Pump Coronary Artery Bypass Grafting Left Ventricular Dysfunction (LVD) Short-Term Outcomes
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Trade-Offs and Synergie Effects of Regulating Ecosystem Services along an Climatic Gradient in Slovakia
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作者 Jarmila Makovníková Stanislav Kološta Boris Pálka 《Journal of Geoscience and Environment Protection》 2024年第6期135-150,共16页
This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We ev... This study aims to assess the synergies and trade-offs of regulating ecosystem services. Ecosystem services are non-linearly interconnected and changes in one service can positively or negatively affect another. We evaluated ecosystem services based on biophysical indicators using an expert scoring system that determines the corresponding soil functions and is part of the existing databases available in Slovakia. This methodological combination enabled us to provide unique mapping and assessment of ecosystem services within Slovakia. Correlation analysis between individual regulating ecosystem services and climate regions, slope, texture, and altitude confirm the statistically significant influence of climate and slope in all agricultural land, arable land, and grassland ecosystems. Statistically significant synergistic effects were established between the regulation of the water regime and the regulation of soil erosion within each climate region, apart from the very warm climate region. Only in a very warm climate region was potential of regulating ecosystem services mutually beneficial for soil erosion control and soil cleaning potential (immobilization of inorganic pollutants). 展开更多
关键词 Agroecosystem Services Climatic Zone MAPPING Trade-offs SYNERGIES
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Efficient Vision Transformers for Autonomous Off-Road Perception Systems
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作者 Max H. Faykus III Adam Pickeral +2 位作者 Ethan Marquez Melissa C. Smith Jon C. Calhoun 《Journal of Computer and Communications》 2024年第9期188-207,共20页
The development of autonomous vehicles has become one of the greatest research endeavors in recent years. These vehicles rely on many complex systems working in tandem to make decisions. For practical use and safety r... The development of autonomous vehicles has become one of the greatest research endeavors in recent years. These vehicles rely on many complex systems working in tandem to make decisions. For practical use and safety reasons, these systems must not only be accurate, but also quickly detect changes in the surrounding environment. In autonomous vehicle research, the environment perception system is one of the key components of development. Environment perception systems allow the vehicle to understand its surroundings. This is done by using cameras, light detection and ranging (LiDAR), with other sensor systems and modalities. Deep learning computer vision algorithms have been shown to be the strongest tool for translating camera data into accurate and safe traversability decisions regarding the environment surrounding a vehicle. In order for a vehicle to safely traverse an area in real time, these computer vision algorithms must be accurate and have low latency. While much research has studied autonomous driving for traversing well-structured urban environments, limited research exists evaluating perception system improvements in off-road settings. This research aims to investigate the adaptability of several existing deep-learning architectures for semantic segmentation in off-road environments. Previous studies of two Convolutional Neural Network (CNN) architectures are included for comparison with new evaluation of Vision Transformer (ViT) architectures for semantic segmentation. Our results demonstrate viability of ViT architectures for off-road perception systems, having a strong segmentation accuracy, lower inference speed and memory footprint compared to previous results with CNN architectures. 展开更多
关键词 Semantic Segmentation off-Road Vision TRANSFORMERS CNNS Autonomous Driving
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Effect of Spray Rails on Takeoff Performance of Amphibian Aircraft
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作者 Soham S. Bahulekar Alberto W. Mello 《World Journal of Engineering and Technology》 2024年第1期117-140,共24页
Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, survei... Amphibian aircraft have seen a rise in popularity in the recreational and utility sectors due to their ability to take off and land on both land and water, thus serving a myriad of purposes, such as aerobatics, surveillance, and firefighting. Such seaplanes must be aerodynamically and hydrodynamically efficient, particularly during the takeoff phase. Naval architects have long employed innovative techniques to optimize the performance of marine vessels, including incorporating spray rails on hulls. This research paper is dedicated to a comprehensive investigation into the potential utilization of spray rails to enhance the takeoff performance of amphibian aircraft. Several spray rail configurations obtained from naval research were simulated on a bare Seamax M22 amphibian hull to observe an approximate 10% - 25% decrease in water resistance at high speeds alongside a 3% reduction in the takeoff time. This study serves as a motivation to improve the design of the reference airplane hull and a platform for detailed investigations in the future to improve modern amphibian design. 展开更多
关键词 Seaplane Spray Rails Hull Optimization Take-off Performance
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基于MODIS数据的Landsat-7 SLC-off影像修复方法研究 被引量:17
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作者 朱长明 沈占锋 +3 位作者 骆剑承 杨辽 胡晓东 沈金祥 《测绘学报》 EI CSCD 北大核心 2010年第3期251-256,共6页
研究如何修复由于扫描行校正器SLC故障而造成的数据坏行,成为国际遥感研究的热点。文章在总结现有的修复方法基础上提出用相同时相的MODIS09数据修复SLC-off数据的方法。该方法采用时空自适应反射率融合模型(STARFM)算法实现MODIS09数据... 研究如何修复由于扫描行校正器SLC故障而造成的数据坏行,成为国际遥感研究的热点。文章在总结现有的修复方法基础上提出用相同时相的MODIS09数据修复SLC-off数据的方法。该方法采用时空自适应反射率融合模型(STARFM)算法实现MODIS09数据和TM/ETM+数据的融合,获得与SLC-off数据相同时相和空间分辨率的融合数据,然后采用局部线性直方图匹配完成对SLC-off数据填充。实验证明该方法修复效果明显好于传统方法,解决了传统修复方法中存在的一些问题,一定程度上提高了ETM+SLC-off数据的利用率。 展开更多
关键词 SLC-off 缝隙数据 修复 MODIS ETM+
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带通配符和One-Off条件的序列模式挖掘 被引量:23
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作者 吴信东 谢飞 +2 位作者 黄咏明 胡学钢 高隽 《软件学报》 EI CSCD 北大核心 2013年第8期1804-1815,共12页
很多应用领域产生大量的序列数据.如何从这些序列数据中挖掘具有重要价值的模式,已成为序列模式挖掘研究的主要任务.研究这样一个问题:给定序列S、支持度阈值和间隔约束,从序列S中挖掘所有出现次数不小于给定支持度阈值的频繁序列模式,... 很多应用领域产生大量的序列数据.如何从这些序列数据中挖掘具有重要价值的模式,已成为序列模式挖掘研究的主要任务.研究这样一个问题:给定序列S、支持度阈值和间隔约束,从序列S中挖掘所有出现次数不小于给定支持度阈值的频繁序列模式,并且要求模式中任意两个相邻元素在序列中的出现位置满足用户定义的间隔约束.设计了一种有效的带有通配符的模式挖掘算法One-Off Mining,模式在序列中的出现满足One-Off条件,即模式的任意两次出现都不共享序列中同一位置的字符.在生物DNA序列上的实验结果表明,One-Off Mining比相关的序列模式挖掘算法具有更好的时间性能和完备性. 展开更多
关键词 数据挖掘 序列模式挖掘 频繁模式 通配符 One-off条件
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Ease-off拓扑修正的准双曲面齿轮齿面修形方法 被引量:20
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作者 聂少武 蒋闯 +3 位作者 邓效忠 苏建新 杨建军 王建华 《中国机械工程》 EI CAS CSCD 北大核心 2019年第22期2709-2715,2740,共8页
为了提升驱动桥准双曲面齿轮传动的啮合性能,针对准双曲面齿轮刀倾半展成法(HFT)提出一种Ease-off拓扑修正方法。在建立齿面共轭啮合数学模型的基础上,推导出小轮基准齿面方程,通过计算小轮实际齿面与基准齿面之间的偏差,构建出Ease-of... 为了提升驱动桥准双曲面齿轮传动的啮合性能,针对准双曲面齿轮刀倾半展成法(HFT)提出一种Ease-off拓扑修正方法。在建立齿面共轭啮合数学模型的基础上,推导出小轮基准齿面方程,通过计算小轮实际齿面与基准齿面之间的偏差,构建出Ease-off拓扑。借助二阶多项表达式对Ease-off拓扑分解,计算出齿面失配系数,通过调整齿面失配系数构建出修正Ease-off拓扑。通过比较当前Ease-off拓扑与修正Ease-off拓扑,消除小轮当前齿面与修正齿面之间的偏差,反求出小轮加工参数。最后以一对准双曲面齿轮为例进行齿面拓扑修形与磨齿加工,实际齿面印痕与仿真结果一致,验证了齿面拓扑修形方法的有效性。齿面加载接触分析结果表明,修形后齿面接触应力分布得到了改善,实际载荷下齿面接触重合度增加,从而验证了修形方案的合理性。 展开更多
关键词 准双曲面齿轮 共轭齿面 Ease-off修正 拓扑修形 加载接触分析
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基于Landsat-7 ETM+SLC-OFF影像的山地冰川流速提取与评估——以Karakoram锡亚琴冰川为例 被引量:15
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作者 孙永玲 江利明 +2 位作者 柳林 孙亚飞 汪汉胜 《冰川冻土》 CSCD 北大核心 2016年第3期596-603,共8页
Landsat-7机载扫描行校正器(Scan Line Corrector,SLC)失效后的ETM+影像(SLC-OFF影像)约有22%的数据缺失,严重限制了该影像在冰川研究中的应用,特别对长期缺乏高质量遥感影像的高亚洲地区冰川运动连续监测产生较大影响.以Karakoram中部... Landsat-7机载扫描行校正器(Scan Line Corrector,SLC)失效后的ETM+影像(SLC-OFF影像)约有22%的数据缺失,严重限制了该影像在冰川研究中的应用,特别对长期缺乏高质量遥感影像的高亚洲地区冰川运动连续监测产生较大影响.以Karakoram中部最大的锡亚琴冰川为例,初步评估了Landsat-7 ETM+SLC-OFF影像在山地冰川表面流速提取方面的适用性和可行性.选取2009年和2010年两景SLC-OFF影像,运用局部直方图匹配法(Local Linear Histogram Match,LLHM)和加权线性回归法(Weighted Liner Regression,WLR)修复缺失数据条带,并利用亚像元互相关方法对修复后两景影像进行冰川表面流速估算.结果表明,LLHM和WLR两种方法均能有效修复冰川区Landsat-7 SLC-OFF影像,其冰流估算结果与同期Landsat-5 TM影像的冰流结果较为一致,三者冰流速估算精度分别为±5.9 m·a^(-1)、±6.3 m·a^(-1)和±4.0 m·a^(-1),验证了Landsat-7 SLC-OFF影像在山地冰川流速监测中的应用潜力. 展开更多
关键词 Landsat-7 ETM+SLC-off影像 条带修复 山地冰川流速 锡亚琴冰川 Karakoram地区
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基于齿面Ease off拓扑的弧齿锥齿轮齿面偏差等效修正方法 被引量:8
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作者 聂少武 邓静 +2 位作者 邓效忠 杨建军 李聚波 《中国机械工程》 EI CAS CSCD 北大核心 2017年第20期2434-2440,共7页
为提高弧齿锥齿轮齿面修正的效率,提出了一种仅修正小轮齿面偏差的等效修正方法。通过比较实测齿面与设计齿面Ease off之间的失配值,计算出小轮齿面等效偏差。通过建立齿面等效偏差与加工参数之间的修正数学模型,反求出满足理论失配要... 为提高弧齿锥齿轮齿面修正的效率,提出了一种仅修正小轮齿面偏差的等效修正方法。通过比较实测齿面与设计齿面Ease off之间的失配值,计算出小轮齿面等效偏差。通过建立齿面等效偏差与加工参数之间的修正数学模型,反求出满足理论失配要求的小轮加工参数。实验结果表明:通过对小轮齿面偏差进行等效修正,小轮实际齿面与大轮实际齿面之间的失配值与设计值误差在5μm以内,传动误差幅值与理论值相差0.5″,实际齿面啮合结果满足理论设计要求。 展开更多
关键词 弧齿锥齿轮 齿面Ease off拓扑 齿面偏差 等效修正
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弹药的热烤(Cook-off)实验 被引量:18
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作者 张蕊 冯长根 陈朗 《火工品》 CAS CSCD 北大核心 2002年第4期37-39,共3页
热烤试验(Cook-off test)是评估武器弹药热安全性的一个重要的实验。本文介绍了Cook-off的定义和Cook-off实验的发展过程、实验方法,对国内外Cook-off实验研究现状和发展方向进行了分析和展望。。
关键词 Cook-off 含能材料 热安全性 武器弹药 热烤试验
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RDX炸药热烤(Cook-off)实验及数值模拟 被引量:20
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作者 冯长根 张蕊 陈朗 《含能材料》 EI CAS CSCD 2004年第4期193-198,共6页
对一种改性的RDX炸药进行了热烤实验。应用热传导理论对实验中炸药的热作用过程进行了分析,并通过软件PHOENICS3.3对RDX在热烤过程中的热响应情况进行了模拟。结果表明,在环境温度较低时,RDX受热发生分解,所放出的热量可以及时地散失到... 对一种改性的RDX炸药进行了热烤实验。应用热传导理论对实验中炸药的热作用过程进行了分析,并通过软件PHOENICS3.3对RDX在热烤过程中的热响应情况进行了模拟。结果表明,在环境温度较低时,RDX受热发生分解,所放出的热量可以及时地散失到环境中,从而不发生爆炸。环境温度较高时,药柱的边沿受热形成局部高温,导致热点火,使药剂发生爆炸。 展开更多
关键词 爆炸力学 热点火 数值模拟 Cook—off实验 RDX炸药
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Topping-off手术治疗腰椎退行性疾病的影像学分析 被引量:9
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作者 陈小龙 海涌 +4 位作者 关立 杨晋才 鲁世保 孟祥龙 郭徽 《中国脊柱脊髓杂志》 CAS CSCD 北大核心 2015年第1期6-12,共7页
目的:评价Topping-off手术治疗连续双节段腰椎退行性疾病的影像学改变。方法 :2008年8月~2012年12月,35例连续双节段腰椎退行性椎管狭窄症(其中上位病变节段为轻或中度退变)患者在我院接受手术治疗。其中男23例,女12例,年龄62.6... 目的:评价Topping-off手术治疗连续双节段腰椎退行性疾病的影像学改变。方法 :2008年8月~2012年12月,35例连续双节段腰椎退行性椎管狭窄症(其中上位病变节段为轻或中度退变)患者在我院接受手术治疗。其中男23例,女12例,年龄62.6±18.9岁(30~79岁)。所有患者均接受腰椎单节段融合(PLIF)+上位节段棘突间动态稳定(置入Coflex)手术(Topping-off手术),其中L4/5置入Coflex+L5/S1融合14例,L3/4置入Coflex+L4/5融合21例。回顾性分析患者术前及末次随访时X线片上Coflex置入节段及其上位相邻节段的椎间隙高度、椎间活动度、椎体偏移、椎间隙角及腰椎前凸角;在MRI上对Coflex置入节段和其上位相邻节段椎间盘退变情况进行改良Pfirrmann分级。结果:患者均安全完成手术,手术时间为112±21min(95~155min),出血量为403±111ml(300~520ml)。均未出现硬脊膜破裂、神经损伤等相关并发症。随访24.8±12.8个月(11~65个月)。术后末次随访时Coflex置入节段及其上位相邻节段椎间隙前缘高度、椎间隙后缘高度与术前比较均无统计学意义(P〉0.05);Coflex置入节段椎间隙角较术前显著性增大(t=-1.8,P〈0.05);Coflex上位相邻节段椎间隙活动度(过伸位角度-过屈位角度)、椎间隙角及腰椎前凸角与术前比较均无统计学意义(P〉0.05)。24例随访2年以上患者MRI检查显示Coflex置入节段及其上位相邻节段椎间盘的改良Pfirrmann分级情况与术前相同。结论:Topping-off手术可以保持Coflex置入节段良好的稳定性,并保留该节段部分运动功能及其上位相邻节段节段正常活动,减少了上位相邻节段退变发生的危险因素。 展开更多
关键词 Topping-off手术 腰椎管狭窄症 相邻节段退变 影像学
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基于Ease-off的螺旋锥齿轮齿面分区修形方法 被引量:7
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作者 严宏志 肖蒙 +2 位作者 胡志安 艾伍轶 明兴祖 《中南大学学报(自然科学版)》 EI CAS CSCD 北大核心 2018年第4期824-830,共7页
为预控双重螺旋法加工的螺旋锥齿轮的啮合性能,研究基于Ease-off的螺旋锥齿轮齿面修形方法。用大轮理论齿面展成得到小轮共轭齿面,基于预设的对称抛物线传动误差和接触迹,将齿面划分为小端、中间接触区、大端共3个区域,并基于局部共轭... 为预控双重螺旋法加工的螺旋锥齿轮的啮合性能,研究基于Ease-off的螺旋锥齿轮齿面修形方法。用大轮理论齿面展成得到小轮共轭齿面,基于预设的对称抛物线传动误差和接触迹,将齿面划分为小端、中间接触区、大端共3个区域,并基于局部共轭原理沿啮合线方向对3个区域进行3段抛物线修形,得到目标齿面;采用Ease-off齿面接触分析方法,对得到的目标齿面啮合性能进行分析。研究结果表明:传动误差的形状、幅值、接触迹线与接触印痕达到预置要求;分区修形方法为双重螺旋法加工的齿轮工作齿面、非工作齿面同步分区修形优化提供了新途径。 展开更多
关键词 螺旋锥齿轮 Ease-off 分区修形 齿面接触
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基于天棚On-Off控制的磁流变半主动悬架研究 被引量:17
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作者 任宏斌 陈思忠 冯占宗 《北京理工大学学报》 EI CAS CSCD 北大核心 2014年第2期148-152,共5页
以平行平板流动模型和Bingham模型为理论基础,推导了磁流变减振器的阻尼力计算公式.在车辆悬架动态性能模拟试验台上对磁流变减振器的示功特性和速度特性进行了试验验证.最后基于天棚on-off控制,利用dSPACE搭建了实车试验平台,并进行了... 以平行平板流动模型和Bingham模型为理论基础,推导了磁流变减振器的阻尼力计算公式.在车辆悬架动态性能模拟试验台上对磁流变减振器的示功特性和速度特性进行了试验验证.最后基于天棚on-off控制,利用dSPACE搭建了实车试验平台,并进行了实际越野路面的道路试验.试验结果表明:与传统被动悬架对比,磁流变半主动悬架能够很好地抑制车身以及驾驶员座椅的低频共振峰值,降低车身垂向振动幅值,提高车辆行驶平顺性和乘坐舒适性. 展开更多
关键词 磁流变减振器 台架试验 半主动悬架 on-off控制
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