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从“朿”“束”互用看“音随形转” 被引量:1
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作者 吴继刚 《西华师范大学学报(哲学社会科学版)》 2021年第3期87-92,共6页
因“朿”“束”互用,导致一批异体字“音随形转”。从本质上看,“音随形转”是对形声字声符表音规律的反用。从形音关系看,音随形转破坏字形、字音间的固有联系,破坏形声字声符的构意作用。从字词关系看,音随形转引起字词关系的变化:破... 因“朿”“束”互用,导致一批异体字“音随形转”。从本质上看,“音随形转”是对形声字声符表音规律的反用。从形音关系看,音随形转破坏字形、字音间的固有联系,破坏形声字声符的构意作用。从字词关系看,音随形转引起字词关系的变化:破坏字词之间的对应关系,破坏原词的读音与词义。但利用“朿”“束”异写规律,却可沟通一批异体字,考释一些隐性疑难字。 展开更多
关键词 构件 “朿” “束” 互用 “音随形转”
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成釉细胞瘤的锥形束CT表现分析 被引量:5
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作者 罗晶晶 游梦 +2 位作者 文陈妮 许来青 郑广宁 《华西口腔医学杂志》 CAS CSCD 北大核心 2014年第4期373-377,共5页
目的对成釉细胞瘤的锥形束CT(CBCT)表现进行总结分析,为其临床诊断提供依据。方法对病理确诊的有完整CBCT影像资料的37例成釉细胞瘤病例进行回顾性分析,观察其不同CBCT表现。结果 37例资料中,31例为原发病例,6例为复发病例。CBCT表现:3... 目的对成釉细胞瘤的锥形束CT(CBCT)表现进行总结分析,为其临床诊断提供依据。方法对病理确诊的有完整CBCT影像资料的37例成釉细胞瘤病例进行回顾性分析,观察其不同CBCT表现。结果 37例资料中,31例为原发病例,6例为复发病例。CBCT表现:37例病变中,有36例(97.3%)为骨内型,其中多房型17例,单房型17例,蜂窝型2例;1例(2.7%)为骨外型,即软组织型。88.2%(15/17)多房型病变内见舌形嵴;34例(94.4%)颌骨呈唇颊侧或(和)腭舌侧膨隆,颌骨骨密质局部不连续。结论 CBCT检查能精确地反映成釉细胞瘤病变形态和内部结构,对其术前诊断及手术计划具有重要的指导意义。 展开更多
关键词 成釉细胞瘤 临床诊断
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下颌管分支的锥形束CT影像学分析 被引量:2
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作者 郭毅 张巧红 韩晓倩 《华西口腔医学杂志》 CAS CSCD 北大核心 2015年第2期158-160,共3页
目的运用锥形束CT(CBCT)分析下颌管分支发生的概率及其类型。方法选取拍摄CBCT影像的216例(女104例,男112例)患者为研究对象,对CBCT的下颌管分支影像进行观测并进行分类。结果 216例(432侧)患者中,39例(18.06%)50侧(11.57%)观测到下颌... 目的运用锥形束CT(CBCT)分析下颌管分支发生的概率及其类型。方法选取拍摄CBCT影像的216例(女104例,男112例)患者为研究对象,对CBCT的下颌管分支影像进行观测并进行分类。结果 216例(432侧)患者中,39例(18.06%)50侧(11.57%)观测到下颌管分支,其中女18例(17.31%),男21例(18.75%)。下颌管分支分为4类,第Ⅰ类17侧(3.94%),第Ⅱ类11侧(2.55%),第Ⅲ类20侧(4.63%),第Ⅳ类2侧(0.46%)。结论 CBCT对下颌管分支的检出率较高,口腔颌面外科医生在进行下颌手术时应注意下颌管分支这一解剖变异。 展开更多
关键词 下颌管分支 锥形CT 解剖学 放射影像学
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根尖周病中锥形束CT与根尖片识别病损差异的研究进展 被引量:5
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作者 高静 申静 《华西口腔医学杂志》 CAS CSCD 北大核心 2015年第2期209-213,共5页
随着影像学技术的进步,锥形束CT(CBCT)作为口腔临床检查的一种辅助手段,已经广泛应用于口腔医学的各个领域。它具有分辨率高、辐射量低、成像迅速、三维重建、失真小、对硬组织成像好等诸多优点。传统的根尖片是以二维图像的形式显示三... 随着影像学技术的进步,锥形束CT(CBCT)作为口腔临床检查的一种辅助手段,已经广泛应用于口腔医学的各个领域。它具有分辨率高、辐射量低、成像迅速、三维重建、失真小、对硬组织成像好等诸多优点。传统的根尖片是以二维图像的形式显示三维物体及其周围结构,仅显示重叠的近远中向骨质破坏,不能显示颊舌向骨质破坏。CBCT作为一种三维成像技术,可以从矢状位、冠状位和轴位显示组织的三维结构,克服了根尖片二维图像重叠、变形等缺陷。CBCT的三维成像技术较传统根尖片具有独特优势,与根尖片相比,CBCT在观察骨质结构和根尖骨质破坏方面具有更高的灵敏度。本文就CBCT与根尖片在根尖病损识别中的差异研究进展作一综述。 展开更多
关键词 根尖周病 根尖片
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基于谱图和约束NMF的滚动轴承特征频谱提取算法
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作者 崔得龙 张清华 +1 位作者 肖明 王磊 《轴承》 北大核心 2014年第5期48-52,共5页
为了克服传统时频分析中信号特征频谱提取技术中参数敏感问题,设计了一种基于谱图和约束NMF的特征频谱提取算法。该算法首先对振动信号进行归一化预处理和短时Fourier分析,获得代表原始非平稳信号特性的瞬时参数即谱图;然后对谱图进行约... 为了克服传统时频分析中信号特征频谱提取技术中参数敏感问题,设计了一种基于谱图和约束NMF的特征频谱提取算法。该算法首先对振动信号进行归一化预处理和短时Fourier分析,获得代表原始非平稳信号特性的瞬时参数即谱图;然后对谱图进行约束NMF分解;最后由基矩阵获得原始振动信号的特征频谱。理论分析、仿真和工程试验验证了该算法的可行性和有效性。 展开更多
关键词 滚动轴承 故障诊断 谱图 特征频谱
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锥形束CT、根管测量仪在早期诊断牙根纵裂中的应用 被引量:1
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作者 刘新莉 《国际医药卫生导报》 2015年第9期1221-1222,1326,共3页
目的 应用锥形束CT、根管测量仪早期诊断未经牙髓治疗临床检查疑似磨牙牙根纵裂的价值.方法 对符合条件纳入研究的患牙拍摄X线牙片、锥形束CT,用根管测量仪测量患牙的根管长度并进行比较.利用以上任意一种方法确诊为牙根纵裂者行牙冠半... 目的 应用锥形束CT、根管测量仪早期诊断未经牙髓治疗临床检查疑似磨牙牙根纵裂的价值.方法 对符合条件纳入研究的患牙拍摄X线牙片、锥形束CT,用根管测量仪测量患牙的根管长度并进行比较.利用以上任意一种方法确诊为牙根纵裂者行牙冠半切术与截根术以明确牙根纵裂存在的真实性.三种诊断方法与实际诊断结果相比较并进行统计学分析.结果 不同诊断方法的检出率与准确率分别为X线牙片(45.5%、51.5%)、根管测量仪(75.8%、81.8%)、锥形束CT(84.8%、90.9%).X线牙片分别与锥形束CT、根管测量仪比较,差异有统计学意义(P<0.05).根管测量仪与锥形束CT比较,差异无统计学意义(P>0.05).结论 锥形束CT、根管测量仪可应用在牙根纵裂的早期诊断. 展开更多
关键词 锥形CT 根管测量仪 牙根纵裂 早期诊断
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“炊束”“扫树”“笤帚[·fu]”后字考
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作者 孔国兴 《励耘语言学刊》 CSSCI 2018年第2期276-280,共5页
方言词典、方志所记“炊帚”“扫帚”“笤帚”类词语的后字“帚[·fu]”“束”以及“树”应为指称高粱之“秫”。[fu][t█u]并无音变关系,所涉方言的[f]对应北京话的[█];高粱莛及其穗是制作炊帚、扫帚、笤帚的主要材料,“炊秫”... 方言词典、方志所记“炊帚”“扫帚”“笤帚”类词语的后字“帚[·fu]”“束”以及“树”应为指称高粱之“秫”。[fu][t█u]并无音变关系,所涉方言的[f]对应北京话的[█];高粱莛及其穗是制作炊帚、扫帚、笤帚的主要材料,“炊秫”“扫秫”的构词模式[功用+材料]以及“苕秫”的构词模式[类名+材料]正体现了这一点。 展开更多
关键词 帚[·fu] /树 制作材料 构词模式
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On capped Higgs positivity cone
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作者 Dong-Yu Hong Zhuo-Hui Wang Shuang-Yong Zhou 《中国科学技术大学学报》 CAS CSCD 北大核心 2024年第7期44-54,43,I0003,共13页
The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to ... The Wilson coefficients of the standard model effective field theory are subject to a series of positivity bounds.It has been shown that while the positivity part of the ultraviolet(UV)partial wave unitarity leads to the Wilson coefficients living in a convex cone,further including the nonpositivity part caps the cone from above.For Higgs scattering,a capped positivity cone was obtained using a simplified,linear unitarity condition without utilizing the full internal symmetries of Higgs scattering.Here,we further implement stronger nonlinear unitarity conditions from the UV,which generically gives rise to better bounds.We show that,for the Higgs case in particular,while the nonlinear unitarity conditions per se do not enhance the bounds,the fuller use of the internal symmetries do shrink the capped positivity cone significantly. 展开更多
关键词 positivity bounds standard model effective field theory(SMEFT) HIGGS
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Bearing mechanism of roof and rib support structure in automatically formed roadway and its support design method
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作者 JIANG Bei WANG Ming-zi +4 位作者 WANG Qi XIN Zhong-xin XING Xue-yang DENG Yu-song YAO Liang-di 《Journal of Central South University》 SCIE EI CAS CSCD 2024年第7期2467-2487,共21页
Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the succ... Non-pillar mining technology with automatically formed roadway is a new mining method without coal pillar reservation and roadway excavation.The stability control of automatically formed roadway is the key to the successful application of the new method.In order to realize the stability control of the roadway surrounding rock,the mechanical model of the roof and rib support structure is established,and the influence mechanism of the automatically formed roadway parameters on the compound force is revealed.On this basis,the roof and rib support structure technology of confined lightweight concrete is proposed,and its mechanical tests under different eccentricity are carried out.The results show that the bearing capacity of confined lightweight concrete specimens is basically the same as that of ordinary confined concrete specimens.The bearing capacity of confined lightweight concrete specimens under different eccentricities is 1.95 times higher than those of U-shaped steel specimens.By comparing the test results with the theoretical calculated results of the confined concrete,the calculation method of the bearing capacity for the confined lightweight concrete structure is selected.The design method of confined lightweight concrete support structure is established,and is successfully applied in the extra-large mine,Ningtiaota Coal Mine,China. 展开更多
关键词 automatically roadway with non-pillar confined lightweight concrete roof and rib support mechanical model bearing behaviour
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Microstructural evolution and dynamic recrystallization mechanisms of additively manufactured TiAl alloy with heterogeneous microstructure during hot compression
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作者 Hui TAO Hui-zhong LI +5 位作者 Jia-hui LI Li WANG Wei-wei HE Xiao-fen TAN Rui ZHOU Xiao-peng LIANG 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2024年第10期3208-3220,共13页
Microstructural evolution and dynamic recrystallization(DRX)mechanisms of a Ti-48Al-2Cr-2Nb(at.%)alloy prepared by selective electron beam melting(SEBM)during hot deformation at 1150℃and 0.1 s^(-1)were investigated b... Microstructural evolution and dynamic recrystallization(DRX)mechanisms of a Ti-48Al-2Cr-2Nb(at.%)alloy prepared by selective electron beam melting(SEBM)during hot deformation at 1150℃and 0.1 s^(-1)were investigated by hot compression tests,optical microscope(OM),scanning electron microscope(SEM),electron back-scattered diffraction(EBSD)and transmission electron microscope(TEM).The results show that the initial microstructure of the as-SEBMed alloy exhibits layers of coarseγgrains and fineγ+α_(2)+(α_(2)/γ)lamellar mixture grains alternately along the building direction.During the early stage of hot deformation,deformation twins tend to form within the coarse grains,facilitating subsequent deformation,and a small number of DRX grains appear in the fine-grained regions.With the increase of strain,extensive DRX grains are formed through different DRX mechanisms in both coarse and fine-grained regions,involving discontinuous dynamic recrystallization mechanism(DDRX)in the fine-grained regions and a coexistence of DDRX and continuous dynamic recrystallization(CDRX)in the coarsegrained regions. 展开更多
关键词 TiAl alloy selective electron beam melting heterogeneous microstructure discontinuous dynamic recrystallization(DDRX) continuous dynamic recrystallization(CDRX)
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Polypyrimidine Tract-Binding Protein Enhances Zika Virus Translation by Binding to the 5'UTR of Internal Ribosomal Entry Site
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作者 Moliduer Hamiti Xin-Tian Zhang +4 位作者 Rui-Min Zhu Yun-Peng Liu Bin Yin Peng-Cheng Shu Xiao-Zhong Peng 《Chinese Medical Sciences Journal》 CAS CSCD 2024年第3期163-172,共10页
Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located... Objectives To identify the 5'untranslated region of Zika virus(ZIKV 5'UTR)RNA-binding proteins and to investigate the impact of the binding protein on the activity of internal ribosomal entry site(IRES)located in ZIKV 5'UTR and virus production.Methods Interacting proteins in U251 cells were captured using tRSA-tagged ZIKV 5'UTR RNA and tRSA-ZIKV 5'UTR RNA-binding proteins were visualized by SDS-PAGE silver staining,Subsequently,liquid chromatographytandem mass spectrometry(LC-MS/MS),bioinformatics analysis,and Western blot were used to identify the candidate proteins binding to ZIKV 5'UTR.Dicistronic expression assay and plaque forming assay were performed to analyze the effect of the binding protein on ZIKV IRES activity and ZIKV production,respecitvely.Results tRSA RNA pull-down assay,LC-MS/MS,and Western blot analysis showed that polypyrimidine tractbinding protein(PTB)bound to the ZIKV 5'UTR.Furthermore,dual luciferase reporter assay revealed that overexpression of PTB significantly enhanced the IRES activity of ZIKV(t=10.220,P<0.001),while PTB knockdown had the opposite effect(t=4.897,P<0.01).Additionally,virus plaque forming assay demonstrated that up-regulation of PTB expression significantly enhanced viral titer(t=6.400,P<0.01),whereas reducing PTB expression level weakened virus infectivity(t=5.055,P<0.01).Conclusion PTB positively interacts with the ZIKV 5'UTR and enhances IRES activity and virus production. 展开更多
关键词 internal ribosomal entry site polypyrimidine tract-binding protein Zika virus tRSA RNA pull-down dual-luciferase reporter assay
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B位掺杂对Pb[(Mn_(1/3)Nb_(2/3))_(0.5)(Mn_(1/3)Sb_(2/3))_(0.5)]_x(Zr_(0.825)Ti_(0.175))_(1-x)O_3系陶瓷铁电畴反转的影响 被引量:3
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作者 姜胜林 仝金雨 +1 位作者 张海波 任伏龙 《硅酸盐学报》 EI CAS CSCD 北大核心 2007年第3期303-307,共5页
用传统陶瓷工艺制备了Pb[(Mn1/3Nb2/3)0.5(Mn1/3Sb2/3)0.5]x(Zr0.825Ti0.175)1-xO3(其中x为B位掺杂的摩尔分数,下同)系铁电陶瓷,研究了室温条件下电滞回线的特性。结果显示:当x≤0.1时,电滞回线出现“束腰”;当x=0.2时,“束腰”消失。用... 用传统陶瓷工艺制备了Pb[(Mn1/3Nb2/3)0.5(Mn1/3Sb2/3)0.5]x(Zr0.825Ti0.175)1-xO3(其中x为B位掺杂的摩尔分数,下同)系铁电陶瓷,研究了室温条件下电滞回线的特性。结果显示:当x≤0.1时,电滞回线出现“束腰”;当x=0.2时,“束腰”消失。用X射线光电子能谱、X射线衍射分析手段研究了“束腰”现象,并用氧缺位内偏场理论分析该现象的微观机理。结果表明:过量Mn偏析于晶界,使材料的晶界具有p型导电性,偏析Mn的量越多,晶界p型导电性越强,氧缺位钉扎电畴的能力下降,电畴容易反转,进而导致“束腰”现象消失。另外,随着x增大,剩余极化强度先增大后减小,矫顽场逐渐增大。 展开更多
关键词 铁电陶瓷 电滞回线 “束腰”现象
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Structure and mechanical properties of aluminum alloy/Ag interlayer/steel non-centered electron beam welded joints 被引量:6
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作者 张秉刚 陈国庆 +1 位作者 张春光 倪家强 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第12期2592-2596,共5页
Electron beam welding was carried out between aluminum alloy and steel with Ag interlayer. Seam morphology, structure and mechanical properties of the joints were investigated with different action positions of the el... Electron beam welding was carried out between aluminum alloy and steel with Ag interlayer. Seam morphology, structure and mechanical properties of the joints were investigated with different action positions of the electron beam spot. The results show that with the increment of the beam offset to the silver side from the interface between silver and steel, the seam morphology was improved, and the porosity in the Ag interlayer vanished. A transition layer mainly composed of Ag2Al and Al eutectic was formed at the interface between silver and aluminum, and became thin and spiccato as the beam offset increased. When the beam offset was too large, two IMC layers composed of FeAl and FeAl3 respectively were formed at the interface between steel and Ag interlayer. The optimal beam offset was 0.2 mm, and the maximum tensile strength of the joint was 193 MPa, 88.9% that of the aluminum alloy, and the fracture occurred at the interface between steel and Ag interlayer. 展开更多
关键词 aluminum alloy STEEL Ag interlayer non-centered electron beam welding joint
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Estimating primaries by sparse inversion of the 3D Curvelet transform and the L1-norm constraint 被引量:7
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作者 冯飞 王德利 +1 位作者 朱恒 程浩 《Applied Geophysics》 SCIE CSCD 2013年第2期201-209,237,共10页
In this paper, we built upon the estimating primaries by sparse inversion (EPSI) method. We use the 3D curvelet transform and modify the EPSI method to the sparse inversion of the biconvex optimization and Ll-norm r... In this paper, we built upon the estimating primaries by sparse inversion (EPSI) method. We use the 3D curvelet transform and modify the EPSI method to the sparse inversion of the biconvex optimization and Ll-norm regularization, and use alternating optimization to directly estimate the primary reflection coefficients and source wavelet. The 3D curvelet transform is used as a sparseness constraint when inverting the primary reflection coefficients, which results in avoiding the prediction subtraction process in the surface-related multiples elimination (SRME) method. The proposed method not only reduces the damage to the effective waves but also improves the elimination of multiples. It is also a wave equation- based method for elimination of surface multiple reflections, which effectively removes surface multiples under complex submarine conditions. 展开更多
关键词 Sparse inversion primary reflection coefficients 3D Curvelet transformation L1regularization convex optimization
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3D electrical resistivity inversion using prior spatial shape constraints 被引量:8
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作者 李术才 聂利超 +4 位作者 刘斌 宋杰 刘征宇 苏茂鑫 徐磊 《Applied Geophysics》 SCIE CSCD 2013年第4期361-372,510,共13页
To minimize the number of solutions in 3D resistivity inversion, an inherent problem in inversion, the amount of data considered have to be large and prior constraints need to be applied. Geological and geophysical da... To minimize the number of solutions in 3D resistivity inversion, an inherent problem in inversion, the amount of data considered have to be large and prior constraints need to be applied. Geological and geophysical data regarding the extent of a geological anomaly are important prior information. We propose the use of shape constraints in 3D electrical resistivity inversion, Three weighted orthogonal vectors (a normal and two tangent vectors) were used to control the resistivity differences at the boundaries of the anomaly. The spatial shape of the anomaly and the constraints on the boundaries of the anomaly are thus established. We incorporated the spatial shape constraints in the objective function of the 3D resistivity inversion and constructed the 3D resistivity inversion equation with spatial shape constraints. Subsequently, we used numerical modeling based on prior spatial shape data to constrain the direction vectors and weights of the 3D resistivity inversion. We established a reasonable range between the direction vectors and weights, and verified the feasibility and effectiveness of using spatial shape prior constraints in reducing excessive structures and the number of solutions. We applied the prior spatially shape-constrained inversion method to locate the aquifer at the Guangzhou subway. The spatial shape constraints were taken from ground penetrating radar data. The inversion results for the location and shape of the aquifer agree well with drilling data, and the number of inversion solutions is significantly reduced. 展开更多
关键词 electrical resistivity INVERSION prior spatial constraints direction vector GEOPHYSICS geotechnical engineering.
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Prestack Gaussian beam depth migration under complex surface conditions 被引量:11
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作者 岳玉波 李振春 +2 位作者 张平 周学锋 秦宁 《Applied Geophysics》 SCIE CSCD 2010年第2期143-148,194,共7页
In areas with a complex surface,the acquisition and processing of seismic data is a great challenge.Although elevation-static corrections can be used to eliminate the influences of topography,the distortions of seismi... In areas with a complex surface,the acquisition and processing of seismic data is a great challenge.Although elevation-static corrections can be used to eliminate the influences of topography,the distortions of seismic wavefields caused by simple vertical time shifts still greatly degrade the quality of the migrated images.Ray-based migration methods which can extrapolate and image the wavefields directly from the rugged topography are efficient ways to solve the problems mentioned above.In this paper,we carry out a study of prestack Gaussian beam depth migration under complex surface conditions.We modify the slant stack formula in order to contain the information of surface elevations and get an improved method with more accuracy by compositing local plane-wave components directly from the complex surface.First,we introduce the basic rules and computational procedures of conventional Gaussian beam migration.Then,we give the original method of Gaussian beam migration under complex surface conditions and an improved method in this paper.Finally,we validate the effectiveness of the improved method with trials of model and real data. 展开更多
关键词 complex surface local plane-wave Gaussian beam migration
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Low-frequency data analysis and expansion 被引量:9
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作者 张军华 张彬彬 +2 位作者 张在金 梁鸿贤 葛大明 《Applied Geophysics》 SCIE CSCD 2015年第2期212-220,275,共10页
The use of low-frequency seismic data improves the seismic resolution, and the imaging and inversion quality. Furthermore, low-frequency data are applied in hydrocarbon exploration; thus, we need to better use low-fre... The use of low-frequency seismic data improves the seismic resolution, and the imaging and inversion quality. Furthermore, low-frequency data are applied in hydrocarbon exploration; thus, we need to better use low-frequency data. In seismic wavelets, the loss of low-frequency data decreases the main lobe amplitude and increases the first side lobe amplitude and results in the periodic shocking attenuation of the secondary side lobe. The loss of low frequencies likely produces pseudo-events and the false appearance of higher resolution. We use models to examine the removal of low-frequency data in seismic data processing. The results suggest that the removal of low frequencies create distortions, especially for steep structures and thin layers. We also perform low-frequency expansion using compressed sensing and sparse constraints and develop the corresponding module. Finally, we apply the proposed method to real common image point gathers with good results. 展开更多
关键词 seismic wavelet forward modeling low-frequency expansion compressed sensing sparse constraint
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4D-CBCT图像引导技术在食管癌精确放疗中的应用 被引量:5
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作者 葛小林 李金凯 +8 位作者 王沛沛 李彩虹 陈佳艳 曹远东 张胜 杨焱 李丹明 穆庆霞 孙新臣 《临床肿瘤学杂志》 CAS 2014年第11期1011-1014,共4页
目的探讨利用四维锥形束CT(4D-CBCT)监测食管癌精确放疗中的摆位误差,为勾画食管癌合理的计划靶区(PTV)提供依据。方法采用医科达Axesse直线加速器机载4D-CBCT对16例食管癌患者精确放疗前行扫描,系统自动重建图像并与治疗计划CT图像相匹... 目的探讨利用四维锥形束CT(4D-CBCT)监测食管癌精确放疗中的摆位误差,为勾画食管癌合理的计划靶区(PTV)提供依据。方法采用医科达Axesse直线加速器机载4D-CBCT对16例食管癌患者精确放疗前行扫描,系统自动重建图像并与治疗计划CT图像相匹配,获得患者在头脚(SI)、左右(LR)、前后(AP)方向上的摆位误差,经过自动校正后,再次行4D-CBCT扫描,并按照同样的匹配方式与计划CT进行配准,采集校正后三维方向上的摆位误差。结果 16例患者共获166次扫描。校正前,4D-CBCT图像在SI、LR、AP方向的摆位误差分别为(5.6±0.4)mm、(3.4±0.5)mm和(2.2±0.2)mm,经过校正后在SI、LR、AP方向的摆位误差分别为(1.6±0.2)mm、(0.2±0.1)mm和(0.3±0.2)mm。摆位误差调整前在LR、SI、AP方向上临床靶区(CTV)到PTV外放边界分别为7.3mm、9.4mm和7.6mm,调整后分别为3.0mm、4.6mm和2.5mm。结论利用4D-CBCT图像在治疗前进行误差校准,可以明显缩小摆位误差,更加准确地勾画食管癌PTV的范围,提高食管癌的放疗精度。 展开更多
关键词 锥形CT 图像引导的放射治疗 摆位误差 食管癌
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Temperature and stress fields in electron beam welded Ti-15-3 alloy to 304 stainless steel joint with copper interlayer sheet 被引量:9
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作者 张秉刚 王廷 +2 位作者 段潇辉 陈国庆 冯吉才 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第2期398-403,共6页
Electron beam welding of Ti-15-3 alloy to 304 stainless steel (STS) using a copper filler metal was carried out. The temperature fields and stress distributions in the Ti/Fe and Ti/Cu/Fe joint during the welding pro... Electron beam welding of Ti-15-3 alloy to 304 stainless steel (STS) using a copper filler metal was carried out. The temperature fields and stress distributions in the Ti/Fe and Ti/Cu/Fe joint during the welding process were numerically simulated and experimentally measured. The results show that the rotated parabola body heat source is fit for the simulation of the electron beam welding. The temperature distribution is asymmetric along the weld center and the temperature in the titanium alloy plate is higher than that in the 304 STS plate. The thermal stress also appears to be in asymmetric distribution. The residual tensile stress mainly exists in the weld at the 304 STS side. The copper filler metal decreases the peak temperature and temperature grade in the joint as well as the residual stress. The longitudinal and lateral residual tensile strengths reduce by 66 MPa and 31 MPa, respectively. From the temperature and residual stress, it is concluded that copper is a good filler metal candidate for the electron beam welding of Ti-15-3 titanium alloy to 304 stainless steel. 展开更多
关键词 Ti-15-3 alloy 304 stainless steel electron beam welding temperature field residual stress
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QTL Analysis of Rice Peduncle Vascular Bundle System and Panicle Traits 被引量:17
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作者 滕胜 钱前 +3 位作者 曾大力 国广泰史 黄大年 朱立煌 《Acta Botanica Sinica》 CSCD 2002年第3期301-306,共6页
A double haploid (DH) population of rice (Oryza sativa L.) derived from anther culture of ZYQ8/JX17, a typical indica and japonica hybrid, was used for genetic analysis of rice peduncle vascular system and panicle tra... A double haploid (DH) population of rice (Oryza sativa L.) derived from anther culture of ZYQ8/JX17, a typical indica and japonica hybrid, was used for genetic analysis of rice peduncle vascular system and panicle traits. The number of large vascular bundles (LVB), the number of small vascular bundles (SVB) in the peduncle, and the panicle traits including the number of primary rachis branches (PRB), the number of spikelets per panicle (SNP), peduncle top diameter (PTD), and panicle length (PL) were investigated in the parents and DH lines. The quantitative trait loci (QTLs) for each trait were analyzed based on the constructed molecular linkage map of this population. Three QTLs for LVB (qLVB_1, qLVB_6 and qLVB_7) were detected on chromosomes 1, 6, and 7, respectively. Two putative QTLs for SVB (qSVB_4 and qSVB_6) were mapped on chromosomes 4 and 6 respectively. Four QTLs (qPRB_4a, qPRB_4b, qPRB_6 and qPRB_7) on chromosomes 4, 6, and 7, respectively, were detected for PRB. Three QTLs (qSPN_4a, qSPN_4b and qSPN_6) were identified on chromosomes 4 and 6, respectively, which could significantly affect SPN. Five QTLs for PTD (qPTD_2, qPTD_5, qPTD_6, qPTD_8 and qPTD_12) were identified on chromosomes 2, 5, 6, 8, and 12, respectively. Three QTLs for PL (qPL_4, qPL_6 and qPL_8) were detected on chromosomes 4, 6, and 8, respectively. Clustering of QTLs, such as qLVB_6, qSVB_6, qSNP_6, qPTD_6, and qPL_6 detected in the interval G122_G1314b on chromosome 6, was found. These results suggest that some QTLs for peduncle vascular bundle system are possibly responsible for the panicle traits. 展开更多
关键词 RICE peduncle vascular bundle panicle traits QTL analysis
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