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Fluvio-hydrological characteristics and diverse bedrock geology control the dynamic growth,truncation,and amalgamation of bedrock streambed and marine potholes
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作者 Biswajit Bera Sumana Bhattacharjee +7 位作者 Uttam Mukhopadhyay Debasis Sengupta Pravat Kumar Shit Nairita Sengupta Supriya Ghosh Arijit Ghosh Soumik Saha Sudipa Sarkar 《River》 2025年第1期84-105,共22页
A total of 393 potholes(368 fluvial and 25 marine potholes)were studied at seven different sites in both the fluvial and marine environments.Diverse bedrock properties and large-scale delivery of tools and grinders re... A total of 393 potholes(368 fluvial and 25 marine potholes)were studied at seven different sites in both the fluvial and marine environments.Diverse bedrock properties and large-scale delivery of tools and grinders regulate the dynamic growth,truncation,and amalgamation of potholes.Therefore,the principal objectives of the study are(i)to examine the relationship between the growth of potholes and substrate lithological with structural characteristics(applying geospatial and Schmidt hammer for rock strength analysis)and(ii)to measure the morphology,and size of tools and grinders,processes of truncation and amalgamation in hydro-geomorphic environment using various indices and field techniques.The result showed that large potholes are stretched in the direction of lineament axes and roughly parallel to the river flow direction.Here,the steady growth of pothole depth-diameter is controlled by active bedrock structures,tools,or grinders,and monsoonal high-velocity bank full discharge.Consequently,the deepening and widening of potholes are relatively slow at Bindu,Deuli,and marine beach Neil Island due to fewer structures and little supply of tools or grinders.In small stretches,(Damodar,Subarnarekha,and Rarhu)canyons and gorge-like features(bedrock incision)are formed at Rajrappa,Bhakuyadi,and Guridih sites due to cyclic truncation and amalgamation.Truncation and amalgamation processes restrict the vertical depth threshold value of potholes within 3m,particularly at Rajrappa,Bhakuyadi,and Guridih sites.Scientific study of the pothole's dynamic growth is greatly necessary for the different environmental engineering and river hydraulic projects like excavation,dredging,and dam or barrage construction.Successively,it is essential to compute the cost of rock excavation or dredging,primarily for the mechanical strength of the bedrock river channel and its stability. 展开更多
关键词 bedrock structures rock strength Schmidt hammer rebound values toolsand grinders truncation and amalgamation
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超音速气流中层合截锥壳气动弹性特性分析
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作者 石先杰 黄舟 冯佳 《振动工程学报》 北大核心 2026年第2期464-470,共7页
针对飞行器结构在高速气流中面临复杂气动载荷这一工程问题,研究了超音速气流中层合截锥壳气动弹性行为。根据一阶剪切变形理论推导建立了层合截锥壳的动能和应变能方程,并采用带有曲率修正项的线性活塞理论计算确定了气动载荷。基于谱... 针对飞行器结构在高速气流中面临复杂气动载荷这一工程问题,研究了超音速气流中层合截锥壳气动弹性行为。根据一阶剪切变形理论推导建立了层合截锥壳的动能和应变能方程,并采用带有曲率修正项的线性活塞理论计算确定了气动载荷。基于谱几何法构造位移容许函数,利用Rayleigh-Ritz方法求解能量泛函以获得超音速气流中层合截锥壳气动弹性分析模型。通过与现有文献结果对比,验证了文中模型的正确性。在此基础上,分析了材料参数对层合截锥壳气动弹性稳定性的影响,为超音速飞行器的气动弹性设计提供依据和指导。 展开更多
关键词 超音速气流 层合截锥壳 线性活塞理论 谱几何法
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基于多结构域截取策略的沙海蜇磷脂酶A_(2)毒素可溶性表达系统构建与酶活性分析
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作者 王铠露 李荣锋 +4 位作者 马玉珍 刘松 邢荣娥 李鹏程 于华华 《中国海洋大学学报(自然科学版)》 北大核心 2026年第3期91-100,共10页
沙海蜇(Nemopilema nomurai)作为东亚海域最具危害性的水母之一,其毒素中高丰度的磷脂酶A_(2)(PLA_(2))同工酶被认为是引发系统性中毒反应的关键毒性成分。本研究基于转录组数据库,通过序列比对和三维结构模拟,筛选出四个具有典型PLA_(2... 沙海蜇(Nemopilema nomurai)作为东亚海域最具危害性的水母之一,其毒素中高丰度的磷脂酶A_(2)(PLA_(2))同工酶被认为是引发系统性中毒反应的关键毒性成分。本研究基于转录组数据库,通过序列比对和三维结构模拟,筛选出四个具有典型PLA_(2)催化结构域的新型毒液蛋白。通过构建pET-22b和pET-32a异源表达系统,发现全长重组蛋白在大肠杆菌BL21(DE3)体系中均呈现包涵体形式。为得到可溶性磷脂酶A_(2),本研究创新性地采用多结构域截取策略,成功构建截短型PLA_(2)可溶性表达系统(pET-22b-PLA_(2)-3/BL21(DE3)),并进行体外活性检测证实其具有剂量依赖性磷脂水解活性。本研究首次建立了沙海蜇PLA_(2)毒素的可溶性异源表达体系,为深入阐明其毒性作用分子机制及开发特异性解毒剂奠定了基础。 展开更多
关键词 磷脂酶A_(2) 异源表达 结构域截取 水母毒素 沙海蜇
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GT1株弓形虫ROP16蛋白不同功能片段对三阴性乳腺癌细胞表型的影响
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作者 周月 赵志军 《中国兽医科学》 北大核心 2026年第2期175-183,共9页
为了探究Ⅰ型GT1株弓形虫ROP16蛋白不同功能截短体(激酶域与N端保守基序)对三阴性乳腺癌MDA-MB-231细胞周期、增殖、凋亡及迁移的影响,解析其抗肿瘤活性的分子结构关键功能域。首先基于NCBI-CDD预测ROP16功能域,构建ROP16激酶域截短体(3... 为了探究Ⅰ型GT1株弓形虫ROP16蛋白不同功能截短体(激酶域与N端保守基序)对三阴性乳腺癌MDA-MB-231细胞周期、增殖、凋亡及迁移的影响,解析其抗肿瘤活性的分子结构关键功能域。首先基于NCBI-CDD预测ROP16功能域,构建ROP16激酶域截短体(357~707aa)及N端截短体(1~356aa)慢病毒载体;建立MDA-MB-231稳转细胞系,通过CCK8、流式凋亡/周期检测、划痕/Transwell试验评估功能域对细胞表型的影响;结合RT-qPCR、Western-blot分析凋亡相关基因(BAX/BCL2/CASP3)的m RNA及蛋白表达。结果显示,ROP161~356截短体可显著抑制MDA-MB-231细胞增殖(P<0.05),促进细胞凋亡(P<0.05),引起G2/M期阻滞,同时上调促凋亡因子BAX、Caspase3表达;而ROP16357~707截短体非但不具抗肿瘤活性,反而促进细胞增殖(P<0.05),加速有丝分裂进程,并显著增强细胞的转移(P<0.01)及侵袭能力(P<0.05)。本研究首次证实ROP16 N端保守基序(1~356aa)在抗肿瘤作用中起核心作用,揭示了ROP16不同功能截短体对肿瘤细胞的差异性调控,为基于ROP16蛋白开发新型抗肿瘤生物制剂提供了关键理论依据与研究方向。 展开更多
关键词 弓形虫 ROP16蛋白 截短体 MDA-MB-231细胞 表型
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基于平衡截断的锁相环完整结构保留双馈风电机组降阶模型构建
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作者 于潇寒 王睿 +1 位作者 邹亮 孙秋野 《电工技术学报》 北大核心 2026年第3期898-911,共14页
研究表明锁相环已成为导致双馈风电机组低频和次/超同步振荡与同步失准的重要因素。虽然当前模型降阶成为实时仿真和控制器设计的重要手段,并得到了广泛的研究,但是传统模型降阶技术多关注于模型精度和模型计算复杂度,无法实现特定参数... 研究表明锁相环已成为导致双馈风电机组低频和次/超同步振荡与同步失准的重要因素。虽然当前模型降阶成为实时仿真和控制器设计的重要手段,并得到了广泛的研究,但是传统模型降阶技术多关注于模型精度和模型计算复杂度,无法实现特定参数或控制环节的机理保留。因此,该文提出一种基于平衡截断的锁相环完整结构保留的双馈风电机组降阶模型构建方法。该方法完整保留了风电机组的动态特性,并解决了降阶系统响应曲线在特定频段内无法贴合全阶系统的问题。首先建立并联双馈风电机组全阶小信号模型;其次,分别将锁相环结构与系统解耦并分离为解耦子系统与解耦主系统;然后,将锁相环中含有的状态变量保留在解耦子系统中,并对解耦主系统应用平衡截断;最后,将解耦子系统与降阶解耦主系统恢复耦合,完成锁相环完整结构的保留和系统降阶。该文以20台双馈风机并联的风电机组为例,验证所提锁相环完整结构保留降阶方法的有效性。 展开更多
关键词 双馈风机 锁相环 小信号稳定性 降阶模型 平衡截断
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基于增强型截断域本征函数展开法的磁屏圆筒铁心线圈电感的解析计算
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作者 禹东泽 陈柏超 +1 位作者 罗垚 向依可 《电工技术学报》 北大核心 2026年第3期749-759,793,共12页
该文运用增强型截断域本征函数展开法(ETREE)提出磁屏圆筒铁心线圈电感的计算公式。在该模型中,铁心磁导率为有限值,而磁屏磁导率可以是有限值,也可以是无穷大。归一化数值本征函数的运用,使得分析过程大为简化。所得的电感计算公式以... 该文运用增强型截断域本征函数展开法(ETREE)提出磁屏圆筒铁心线圈电感的计算公式。在该模型中,铁心磁导率为有限值,而磁屏磁导率可以是有限值,也可以是无穷大。归一化数值本征函数的运用,使得分析过程大为简化。所得的电感计算公式以有限元仿真进行了验证。数值计算结果表明,该文提出的计算公式与有限元仿真对比,其结果误差不超过0.5%,同时具有令人满意的计算效率。 展开更多
关键词 磁屏 铁心线圈电感 增强型截断域本征函数展开法 电感计算
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Empirical Bayes Absolute Error Loss Estimation for Parameter of One-Side Truncation Distribution Families
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作者 李金平 《Chinese Quarterly Journal of Mathematics》 CSCD 1992年第2期20-22,共3页
In this paper we propose an absolute error loss EB estimator for parameter of one-side truncation distribution families. Under some conditions we have proved that the convergence rates of its Bayes risk is o, where 0&... In this paper we propose an absolute error loss EB estimator for parameter of one-side truncation distribution families. Under some conditions we have proved that the convergence rates of its Bayes risk is o, where 0<λ,r≤1,Mn≤lnln n (for large n),Mn→∞ as n→∞. 展开更多
关键词 one-side truncation distribution families absolute error loss function empirical Bayes estimator convergence rates
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基于频谱截断的稀疏SAR无模糊成像方法
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作者 周敏 宋宇凡 +1 位作者 张晶晶 毕辉 《信号处理》 北大核心 2026年第2期171-182,共12页
合成孔径雷达(Synthetic Aperture Radar,SAR)图像中常存在一些特有伪影,其中有限脉冲重复频率(Pulse Repetition Frequency,PRF)和非理想天线方向图引起的方位模糊尤为突出。与此同时,随着对高分辨率与宽覆盖需求的提升,SAR系统往往需... 合成孔径雷达(Synthetic Aperture Radar,SAR)图像中常存在一些特有伪影,其中有限脉冲重复频率(Pulse Repetition Frequency,PRF)和非理想天线方向图引起的方位模糊尤为突出。与此同时,随着对高分辨率与宽覆盖需求的提升,SAR系统往往需要降低PRF以扩展测绘带宽并减少数据量,但这将进一步加剧方位模糊,严重影响图像质量。现有方法通常难以在不降低图像分辨率的情况下快速实现方位模糊抑制。近年来,L_(1)正则化技术因其对欠采样回波数据的优越重建性能受到广泛关注,但对于降PRF回波数据,传统基于L_(1)正则化的稀疏SAR成像方法仍难以满足高质量成像需求。针对上述问题,本文提出了一种基于频谱截断的稀疏SAR无模糊成像方法,在利用迭代阈值收缩算法(Iterative Shrinkage-Thresholding Algorithm,ISTA)求解成像模型的L_(1)范数优化问题时,对迭代过程进行了改进,实现了无模糊成像。该方法在每次迭代过程中,对当前残差进行多普勒频谱截断,分别对原始残差和截断残差进行匹配滤波(Matched Filtering,MF)成像,并逐像素比较保留较小值。若较小值来自截断残差,则对其缩放以增强模糊抑制效果。最终,高分辨率、低模糊的残差用于更新图像估计。仿真结果表明,所提方法在保持传统基于L_(1)正则化的稀疏SAR成像方法抑制噪声和杂波能力的同时,能有效抑制方位模糊。此外,其计算复杂度与传统稀疏SAR成像方法相当,这为大场景高分辨率无模糊重建提供了可行的技术参考。 展开更多
关键词 合成孔径雷达 方位模糊 频谱截断 L_(1)正则化
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Retraction: Truncated Bid Overexpression Induced by Recombinant Adenovirus Cre/LoxP System Suppresses the Tumorigenic Potential of CD133+ Ovarian Cancer Stem Cells
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作者 Oncology Research Editorial Office 《Oncology Research》 2026年第1期620-620,共1页
The published article titled“Truncated Bid Overexpression Induced by Recombinant Adenovirus Cre/LoxP System Suppresses the Tumorigenic Potential of CD133+Ovarian Cancer Stem Cells”has been retracted from Oncology Re... The published article titled“Truncated Bid Overexpression Induced by Recombinant Adenovirus Cre/LoxP System Suppresses the Tumorigenic Potential of CD133+Ovarian Cancer Stem Cells”has been retracted from Oncology Research,Vol.25,No.4,2017,pp.595–603. 展开更多
关键词 recombinant adenovirus Cre Loxp system CD ovarian cancer stem cells recombinant adenovirus truncated Bid overexpression bid overexpression tumorigenic potential
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Numerical study on truncated column with tendons following the toughness seismic resistant design
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作者 Liu Hongtao Hu Binglin +1 位作者 Kong Pengchao Du Xiuli 《Earthquake Engineering and Engineering Vibration》 2026年第1期141-156,共16页
To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,insp... To enhance the deformation capacity of vertical support columns of underground structures and improve their overall seismic performance,a new truncated column connected by unbonded prestressed tendons is proposed,inspired by the concepts of the toughness seismic resistance and rocking design.Although many experimental and numerical studies have focused on underground structures,research on the behavior of truncated columns remains limited.This paper develops threedimensional(3D)finite element(FE)models for various columns,including cast-in-place column(CIPC)and prestressed tendon truncated column(PTTC),to evaluate the effects of three parameters,including axial compression ratio(ACR),initial tendon stress,and the effect of hole diameter on mechanical performance—specifically deformation capacity,strength,residual deformation and gap width.The results indicate that the deformability and self-centering ability of the prestressed tendon truncated column is obviously superior to the cast-in-place column,but its strength was comparatively lower.The axial compression ratio has obvious effects on seismic performance,especially deformation and residual deformation,while initial tendon stress and hole diameter influence performance only in the case of a small axial compression ratio.This study systematically identifies the influence of various factors on seismic performance.Additionally,this study proposes a method to evaluate the self-centering capability of structures and establishes an empirical relationship between maximum recoverable deformation and the axial compression ratio.The developed numerical model can serve as a tool for future studies to predict the seismic responses of overall subway stations that feature truncated columns. 展开更多
关键词 underground subway prestressed tendon truncated column(PTTC) seismic performance initial tendon stress axial compression ratio finite element model
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E种牛肠道病毒VP1蛋白的截短表达及抗体间接ELISA检测方法的建立
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作者 崔平 刘澜 +3 位作者 李本科 白耀国 李玉坤 管宇 《中国兽医杂志》 北大核心 2026年第2期40-48,共9页
为了开展E种牛肠道病毒(BEV-E)的流行病学调查和抗体筛查,本试验采用原核表达技术对BEV-E外衣壳蛋白VP1进行体外截短表达,采用His-Tag蛋白纯化柱对VP1重组蛋白进行纯化,采用蛋白免疫印迹(WB)方法对重组蛋白进行鉴定。以纯化的VP1重组蛋... 为了开展E种牛肠道病毒(BEV-E)的流行病学调查和抗体筛查,本试验采用原核表达技术对BEV-E外衣壳蛋白VP1进行体外截短表达,采用His-Tag蛋白纯化柱对VP1重组蛋白进行纯化,采用蛋白免疫印迹(WB)方法对重组蛋白进行鉴定。以纯化的VP1重组蛋白作为包被抗原,对反应条件进行优化和确定临界值,建立了检测BEV-E抗体的间接酶联免疫吸附试验(ELISA)检测方法,并进行特异性、灵敏性、重复性、符合率试验和临床样品检测。结果显示,成功表达VP1重组蛋白;间接ELISA检测方法的最佳抗原工作浓度为15.0μg/mL,最佳一抗稀释倍数为1∶80,最佳酶标二抗稀释倍数为1∶3000,最佳封闭液为10%马血清,最佳一抗、酶标二抗、封闭液工作时间分别为30、30、60 min;临界值为0.386;与牛病毒性腹泻病毒、牛传染性鼻气管炎病毒、牛冠状病毒、牛轮状病毒、O型口蹄疫病毒、A型口蹄疫病毒、产肠毒素性大肠杆菌阳性血清均无交叉反应,特异性良好;BEV-E阳性血清1∶25600稀释时仍可检测出阳性,灵敏性较高;批内和批间变异系数均小于10%,重复性良好;该方法与间接免疫荧光检测方法的符合率为92.5%;临床样品检测结果显示,BEV-E抗体平均阳性率为7.88%。结果表明,本试验建立的BEV-E VP1抗体间接ELISA检测方法为开展BEV-E临床诊断和流行病学调查提供了试验依据。 展开更多
关键词 E种牛肠道病毒(BEV-E) VP1蛋白 截短表达 抗体检测 间接ELISA
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基于R-SIS的身份签名方案
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作者 郭冰雨 缪祥华 《计算机技术与发展》 2026年第2期208-214,共7页
针对签名密钥尺寸过长、基于SIS(Short Integer Solution)身份签名运算复杂度较高、安全性不足的问题,提出了一种基于环上小整数解问题的身份签名方案。首先,利用环上陷门生成算法生成公钥矩阵和陷门矩阵,通过哈希函数将用户身份映射至... 针对签名密钥尺寸过长、基于SIS(Short Integer Solution)身份签名运算复杂度较高、安全性不足的问题,提出了一种基于环上小整数解问题的身份签名方案。首先,利用环上陷门生成算法生成公钥矩阵和陷门矩阵,通过哈希函数将用户身份映射至环元素,并生成短向量私钥。其次,执行双峰高斯采样掩码,再结合消息与承诺值生成挑战,计算响应并进行低位截断压缩,最终输出短签名。最后,验证阶段通过恢复近似响应并检查多项式环运算关系与范数界限,完成签名合法性判定。通过理论分析证明了方案在随机预言机模型下的正确性与强不可伪造性,通过分叉引理,将可能的伪造攻击转化为R-SIS(Ring Short Integer Solution)问题的解,从而论证在多项式时间内无法被有效攻击。实验显示签名生成平均耗时15.8 ms,签名验证时间平均值为10.7 ms,表明方案具有良好的稳定性和高效性。且在时间与存储开销方面,相较于其他方案具备显著优势。 展开更多
关键词 身份签名 环上小整数解 双峰高斯 截断低位
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双航行体在并联形式下的高速斜入水数值模拟
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作者 石伏龙 田宇 +3 位作者 李润博 金秋 黎仁杰 毛艺达 《中国舰船研究》 北大核心 2026年第1期132-145,共14页
[目的]为增强水下武器的打击效能并提高射击精度,拟针对截锥头型双航行体在并联配置下的高速斜入水特性展开分析。[方法]首先,基于计算流体力学(CFD)软件STAR-CCM+,采用Realizable k–ε湍流模型来求解雷诺平均方程,并且结合重叠网格技... [目的]为增强水下武器的打击效能并提高射击精度,拟针对截锥头型双航行体在并联配置下的高速斜入水特性展开分析。[方法]首先,基于计算流体力学(CFD)软件STAR-CCM+,采用Realizable k–ε湍流模型来求解雷诺平均方程,并且结合重叠网格技术来精确捕捉流场的特征;然后,采用体积分数(VOF)法与Schnerr–Sauer空化模型相结合的方法来追踪空泡演化特性;最后,针对双航行体在不同倾角和净距下的并联高速斜入水过程进行数值模拟,分析航行器速度和位移的变化规律、压力载荷分布特征以及空泡形态的演化特性。[结果]数值研究结果表明,并联双航行体在8°~18°入水倾角下呈现了完整的跳弹运动过程;随着入水倾角的增加,航行体跳弹现象的出现时间也不断延后,空泡外壁压力和空化强度也随之提高。当净距为1.2D时,并联航行体的空泡与尾迹出现了高度融合现象;当净距增加到1.8D时,其垂向和水平位移达到最大值;随着净距增加至3.2D,空泡演化过程更接近单体入水模式,航行体的运动稳定性逐渐提高,而跳弹现象也有所增强。[结论]当双航行体以不同形式高速斜入水时,其流场和空泡形态均会随之改变,研究成果可为超空泡航行体设计和应用提供参考。 展开更多
关键词 截锥头型双航行体 高速入水 入水角度 临界净距 并联配置 空泡融合 空化演化
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基于二项分布的航空装备测试性试验技术优化设计
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作者 郑少军 《自动化应用》 2026年第1期96-99,共4页
测试性是指通过技术手段发现、隔离和诊断故障的能力,是确保航空装备可靠性、安全性及可维护性的核心要素。针对航空装备测试性试验中普遍存在的试验周期长、故障注入样本量多等问题,提出一种“序贯截尾+定数截尾”的双轨融合试验技术,... 测试性是指通过技术手段发现、隔离和诊断故障的能力,是确保航空装备可靠性、安全性及可维护性的核心要素。针对航空装备测试性试验中普遍存在的试验周期长、故障注入样本量多等问题,提出一种“序贯截尾+定数截尾”的双轨融合试验技术,并在某型航空机载产品上实现初步应用。结果表明,该试验技术可以大幅度提高航空装备测试性指标的评估效率,对于装备产品研制阶段的测试性设计快速迭代具有促进作用。 展开更多
关键词 测试性试验 二项分布 序贯截尾 定数截尾
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Influence of Low Load Truncation Level on Crack Growth for Al 2324-T39 and Al 7050-T7451 被引量:10
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作者 Tian Hailing Bao Rui +2 位作者 Zhang Jianyu Zheng Xiaoling Fei Binjun 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2009年第4期401-406,共6页
Tests with middle-crack tension (M(T)) specimens made of Al 2324-T39 and Al 7050-T7451 are conducted to investigate the influence of low load truncation level on fatigue crack growth. The six different truncated s... Tests with middle-crack tension (M(T)) specimens made of Al 2324-T39 and Al 7050-T7451 are conducted to investigate the influence of low load truncation level on fatigue crack growth. The six different truncated spectra are obtained by removing the small cycles of which amplitudes are less than the specified percentages of the maximum amplitude in the basic flight-by-flight loading spectrum and the remainder of the spectrum is untouched. The tests indicate that the mean level of fatigue crack growth life (FCGL) increases as the load truncation level is enhanced. Considering both the time saving and the influence on FCGL, there is an applicable choice (i.e. spectrum S2 or spectrum S3 in this investigation) for full scale fatigue test. The scatter of FCGL becomes much larger than that under the basic spectrum when the load truncation level is increased to a specified high level, mainly due to the occurrence of crack slanting and branching under the high level truncated loading spectra. 展开更多
关键词 fatigue crack growth aluminum alloys low load truncation flight-by-flight spectrum
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椭圆问题在正三角形网格上的有限差分方法研究
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作者 郭静 许秋燕 《宁夏师范大学学报》 2026年第1期5-17,共13页
针对Poisson方程构建正三角形网格上的有限差分方法,分别利用正三角形网格对矩形区域与正三角形区域进行剖分,依次推导得到5种离散格式.数值实验表明,在矩形区域中,当首尾行节点均为奇数时的离散格式精度最优,且在同等情况下,正三角形... 针对Poisson方程构建正三角形网格上的有限差分方法,分别利用正三角形网格对矩形区域与正三角形区域进行剖分,依次推导得到5种离散格式.数值实验表明,在矩形区域中,当首尾行节点均为奇数时的离散格式精度最优,且在同等情况下,正三角形区域上的离散格式相较于矩形区域上的离散格式更具优势. 展开更多
关键词 POISSON方程 有限差分方法 正三角形网格 截断误差
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Tau truncation in the pathogenesis of Alzheimer's disease:a narrative review 被引量:4
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作者 Dandan Chu Xingyue Yang +5 位作者 Jing Wang Yan Zhou Jin-Hua Gu Jin Miao Feng Wu Fei Liu 《Neural Regeneration Research》 SCIE CAS CSCD 2024年第6期1221-1232,共12页
Alzheimer's disease is characterized by two major neuropathological hallmarks—the extracellularβ-amyloid plaques and intracellular neurofibrillary tangles consisting of aggregated and hyperphosphorylated Tau pro... Alzheimer's disease is characterized by two major neuropathological hallmarks—the extracellularβ-amyloid plaques and intracellular neurofibrillary tangles consisting of aggregated and hyperphosphorylated Tau protein.Recent studies suggest that dysregulation of the microtubuleassociated protein Tau,especially specific proteolysis,could be a driving force for Alzheimer's disease neurodegeneration.Tau physiologically promotes the assembly and stabilization of microtubules,whereas specific truncated fragments are sufficient to induce abnormal hyperphosphorylation and aggregate into toxic oligomers,resulting in them gaining prion-like characteristics.In addition,Tau truncations cause extensive impairments to neural and glial cell functions and animal cognition and behavior in a fragment-dependent manner.This review summarizes over 60 proteolytic cleavage sites and their corresponding truncated fragments,investigates the role of specific truncations in physiological and pathological states of Alzheimer's disease,and summarizes the latest applications of strategies targeting Tau fragments in the diagnosis and treatment of Alzheimer's disease. 展开更多
关键词 Alzheimer's disease cleavage site diagnosis MARKER neurofibrillary tangles PHOSPHORYLATION TAU Tau aggregation therapy truncation
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Hybrid Model Testing Technique for Deep-Sea Platforms Based on Equivalent Water Depth Truncation 被引量:4
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作者 张火明 杨建民 肖龙飞 《China Ocean Engineering》 SCIE EI 2007年第3期401-416,共16页
In this paper, an inner turret moored FPSO which works in the water of 320 m depth, is selected to study the socalled "passively-truncated + numerical-simulation" type of hybrid model testing technique while the tn... In this paper, an inner turret moored FPSO which works in the water of 320 m depth, is selected to study the socalled "passively-truncated + numerical-simulation" type of hybrid model testing technique while the tnmcated water depth is 160 m and the model scale ), = 80. During the investigation, the optimization design of the equivalent-depth truncated system is performed by using the similarity of the static characteristics between the truncated system and the full depth one as the objective function. According to the truncated system, the corresponding physical test model is made. By adopting the coupling time domain simulation method, the tnmcated system model test is numerically reconstructed to carefully verify the computer simulation software and to adjust the corresponding hydrodynamic parameters. Based on the above work, the numerical extrapolation to the full depth system is performed by using the verified computer software and the adjusted hydrodyrmmic parameters. The full depth system model test is then performed in the basin and the results are compared with those from the numerical extrapolation. At last, the implementation procedure and the key technique of the hybrid model testing of the deep-sea platforms are summarized and printed. Through the above investigations, some beneficial conclusions are presented. 展开更多
关键词 hybrid model testing technique equivalent water depth truncation FPSO hydrodynamic response TURRET
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Mooring Truncation Design of a Deepwater SPAR 被引量:4
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作者 王宏伟 罗勇 +1 位作者 胡开业 李腾腾 《Journal of Marine Science and Application》 2010年第2期168-174,共7页
To solve the dimensional limitations of physical models in tests, an equivalent water depth truncated design for a classical SPAR working in 913 m water was investigated. The water depth was reduced to 736m and then t... To solve the dimensional limitations of physical models in tests, an equivalent water depth truncated design for a classical SPAR working in 913 m water was investigated. The water depth was reduced to 736m and then to 552m. As this was done, the mooting line lengths, EA value, and mass per meter were adjusted. Truncation rules and formulas for parameters and truncation factors were proposed. SPAR static characteristics were made to be consistent with those at full water depth. Then further time-domain coupled analysis was carried out for the SPAR when the mooting system experienced waves. The mooring lines were simulated by quasi-static method. Global responses and mooring line forces were found to agree well with test results for a prototype at that water depth. The truncation method proved to be robust and reliable. 展开更多
关键词 SPAR moorin system truncation global response
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Discussion on the influence of truncation of ground motion residual distribution on probabilistic seismic hazard assessment 被引量:3
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作者 Wu Jian Gao Mengtan +1 位作者 Chen Kun Huang Bei 《Earthquake Engineering and Engineering Vibration》 SCIE EI CSCD 2011年第3期379-392,共14页
Recent studies on assessment of a very low annual probability of exceeding (APE) ground motions, 10-4 or less, have highlighted the importance of the upper bound of ground motions when very low probability results a... Recent studies on assessment of a very low annual probability of exceeding (APE) ground motions, 10-4 or less, have highlighted the importance of the upper bound of ground motions when very low probability results are acquired. The truncation level adopted in probabilistic seismic hazard analysis (PSHA) should be determined by an aleatory uncertainty model (i.e., distribution model) of ground motions and the possible maximum and minimum ground motion values of a specific earthquake. However, at the present time, it is impossible to establish the upper bound model for ground motions based on the source characteristics and/or ground motion propagation. McGuire suggested a truncation level be fixed at a number of = 6, or the distribution of residuals be truncated in such a manner that site intensity cannot be greater than the epicenter intensity. This study aims to find a reasonable and feasible truncation level to be used in PSHA when the physical mechanism is not available to find the extreme ground motion. A mathematical analysis of the influence of the truncation level on PSHA, case studies of sites in different seismotectonic settings, and a distribution analysis of ground motion residuals are conducted in this study. It is concluded that = 4 is the minimum acceptable value for engineering applications for APEs within 0.002 to 10-4, and for low APEs, such as 10-5 and 10-6, the value of should be no less than 5 in most regions of China. 展开更多
关键词 truncation of ground motions annual probability of exceeding PSHA distribution of ground motion residuals
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