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Search Results: 1 - 10 of 3770 matches for " 戈革 "
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《海森伯传》译者引言

物理 , 2004,
Abstract: ?《海森伯传》译者引言
《尼耳斯.玻尔的时代》汉译者序

物理 , 2005,
Abstract: ?迄今为止,在世界上用不同文字(丹文、中文、英文、德文、俄文)写出(和印出)的十来种“玻尔传”中,本书是篇幅最大和流传颇广的一种.仅此一端,就可以作为我们翻译和出版这本书的充分理由,因为这样一本书无论如何是有很大的正、反两方面的参考价值的.
戈革诗词选

物理 , 2003,
Abstract: ?戈革,号红莩,一号拜鞠,北京石油大学物理学教授,退休。1922年1月22日生于河北献县前南宫村。1949年毕业于北京大学物理系,1952年毕业于清华大学物理研究所。原习理论物理学,中年后改治量子物理学史,专研尼耳斯·玻尔的生平、工作和思想。平生著译数十种,约1500万言,包括独立完成的尼耳斯·玻尔全集。所撰物理学史文章结集成《史情室文帚》一编。2001年受丹麦女王册封“国旗骑士”,授勋章。专业外,有多种文化爱好,尤嗜治印。
玻尔-海森伯1941年会晤档案文献选
(译)
物理 , 2008,
Abstract: ?同“平”或“等”相联系的数学物理学词汇有方程、(不)等式、平衡、恒等式、全等、等价,等等.其所对应的西文词多有出入,而它们在数学物理语境中的具体含义也有值得推敲之处.
采用混合编程的医学图像配准
谭智峰,郑力,纪庆
计算机科学 , 2011,
Abstract: 在确保低误配率的前提下,如何提高医学图像配准的精度与效率,是一项值得研究的重要课题。为了满足临床需要,提出一种混合编程的配准策略,即通过质心提取技术和小波分解图像的细节增强技术相结合的方式进行预配准,并在这个基础上基于图像的灰度信息,利用powell优化算法和传统的基于最大互信息的相似性测度方法进行细配准,从而得到配准结果。另外,对powell算法的一维搜索方式提出了有别于传统brent算法的改进,使之在保证精度与效率的前提下更适用于图像配准。实验证明,提出的配准策略能很好地避免误配准,配准精度达到了亚像素级,配准的效率也符合临床需求。
纳米自组装γ-Al2O3孔隙结构的核磁共振表征
Nuclear Magnetic Resonance Characterization of Nano Self-Assembly γ-Al2O3 Pore Structure

王琳,肖立志(),郭龙,廖广志,张岩,
- , 2017, DOI: 10.3866/PKU.WHXB201704142
Abstract: 纳米自组装γ-Al2O3具有两种纳米级孔道,可作为适合于大分子扩散的催化剂载体,也可用于页岩气藏模型。表征纳米材料孔隙结构的方法有扫描电镜、氮吸附法及压汞法等,各有局限。本文利用核磁共振弛豫测量对纳米自组装γ-Al2O3孔隙结构进行研究和定量表征,并通过核磁共振实验和数值模拟对纳米自组装γ-Al2O3表面弛豫强度及孔径分布进行探索。结果表明,数值模拟核磁弛豫表征的纳米自组装γ-Al2O3的主体孔径为5-7 nm和30-42 nm,核磁弛豫实验通过误差函数法表征的主体孔径为5-9 nm和29-47 nm。相比于氮吸附仅表征微孔介孔及部分大孔,不能表征大于100 nm孔径,压汞法描述小于10 nm孔径相对不准确等问题,核磁弛豫能够全面表征2.8-315 nm纳米自组装γ-Al2O3的双峰孔隙系统。三个样品S-1、S-2、S-3的横向弛豫时间T2谱小孔大孔波峰的信号幅度比0.603、1.15、1.84直接反映各自的化学小孔大孔氧化铝投料比0.85、1.38、1.7的变化。建立的表征方法可以应用于页岩气微观结构和机理研究中,前景广阔。
Nano self-assembled γ-Al2O3, having two kinds of nano-scale pore structures, which can be used as a catalyst carrier suitable for large molecule diffusion and shale gas reservoir models. Characterization of the pore structures in nanomaterials are scanning electron microscopy, nitrogen adsorption method, mercury injection method, etc. These characterization techniques have their own limitations. This paper utilized nuclear magnetic resonance (NMR) relaxation measurements to study and quantitatively characterize the pore structures of nano self-assembled γ-Al2O3. Random walker simulation and error function analysis were used to explore the surface relaxation strength and pore size distribution of nano self-assembled γ-Al2O3. The random walker simulation results show that the main apertures of nano self-assembled γ-Al2O3 are 5-7 nm and 30-42 nm; NMR experiments through error function analysis show that the main apertures of the nano self-assembled material are 5-9 nm and 29-47 nm. Nitrogen adsorption only characterized the microporous, mesoporous, and part of the macroporous structures. The pore diameters greater than 100 nm cannot be detected by the nitrogen adsorption method. The mercury injection method characterizes apertures of size less than 10 nm relatively inaccurately. Nuclear magnetic relaxation can comprehensively characterize bimodal pore system of nano self-assembled γ-Al2O3 of size 2.8-315 nm. As one of the NMR measurements, the T2 spectrum signal amplitude ratio of three samples, S-1, S-2 and S-3 are 0.603, 1.15, 1.84, directly reflect the variety of their micropores and mesopores chemical Al2O3 material ratio 0.85, 1.38, 1.7 respectively. The suggested method can be applied to the investigation for shale gas pore structure and associated mechanisms
Medical Image Registration with Mixed Programming
采用混合编程的医学图像配准

TAN Zhi-feng,ZHENG Li-ge,JI Qing-ge,
谭智峰
,郑力,纪庆

计算机科学 , 2011,
Abstract: How to improve images registration's precision and efficiency while keeping a low error rate is an important topic worthy of study. In order to meet the need of clinical demand, a mixed programming registration strategy was proposed. In this method, the preregistration is finished by the combination of the extraction of the image's gravity center and the detail enhancing of the image which is generated by wavelet decomposition. On this basis, the process of registration is based on the gray-scale of the images,and it uses the Powell optimization algorithm and the traditional maximum mutual information as the method of measuring the similarity between the images. In addition, we proposed an improvement on the oncdimensional search within Powcll algorithm which is different from the 13rent algorithm, and this makes it more suitable for image registration without losing the accuracy and efficiency. The experiment shows that our registration strategy performs very well in avoiding false registration, and its accuracy reaches sub-pixel level, moreover, its efficiency meets the need of clinical demand.
Joubert综合征合并视网膜发育不良1例
A Case of Joubert Syndrome with Retinal Dysplasia
 [PDF]

王淋淋, 黄宇
Hans Journal of Ophthalmology (HJO) , 2013, DOI: 10.12677/HJO.2013.22002
Abstract:
Joubert综合征(Joubert syndrome, JS)是一种较为罕见的脑干及小脑蚓部先天性发育畸形,属于常染色体隐性遗传性疾病,该病可合并其它器官功能异常,即JS及相关畸形(Joubert Syndrome and Related Disorders, JSRD),如视网膜营养不良、肾囊肿、肝纤维化、多指畸形等[1]。在我国已有几例个案报道,但多未见合并其它器官异常,本例Joubert综合征有合并视网膜发育不良,本文结合相关文献进行讨论。
Joubert syndrome (JS) is a rare autosomal recessive congenital malformation of the brainstem and cerebellar vermiswhich may be associated with other organ dysfunction (Joubert Syndrome and Related Disorders, JSRD), mainly as retinal dystrophy, nephronophthisis, hepatic fibrosis and polydactyly. It had been reported in the previous literature in our country, however, most do not mention other organ dysfunction. In the following case complicated with retinal dysplasia was discussed with relate literature.
基于Legendre伪谱法的空间机器人姿态运动的最优控制
Attitude Optimal Control of Space Robot Based on the Legendre Pseudospectral Method
 [PDF]

陈凯捷, 新生
Journal of Aerospace Science and Technology (JAST) , 2015, DOI: 10.12677/JAST.2015.34010
Abstract:
采用Legendre伪谱法研究自由漂浮双臂空间机器人姿态运动最优控制问题。首先,根据系统动量矩守恒关系,对自由漂浮并带有双臂的平面型空间机器人建立动力学模型,并以系统关节的耗散能为性能指标,给出其最优控制问题描述。然后,利用Legendre伪谱法以多项式参数化近似状态变量与控制变量,微分方程用正交多项式近似,从而将连续最优控制问题转化为一组非线性规划问题求解。为解决空间机器人姿态规划问题提供了一种有效方法。最后,对自由漂浮双臂空间机器人姿态控制进行数值仿真,仿真结果表明Legendre伪谱法对解决该姿态运动最优控制问题的有效性。
The optimal attitude control of free-floating space robot system with dual-arm is discussed in this paper by using Legendre pseudospectral method. The simplified robot system dynamics model is established based on the linear and angular momentum conservation of the system. And the system constraints and performance index function based on system joints dissipation energy are determined to describe the optimal control problem. Then the continuous trajectory optimization is transformed into a discrete nonlinear programming problem (NLP) by using Legendre pseudospectral method. And the energy-optimal solutions are obtained with a NLP solver. An optimal attitude control method for the space robot is obtained. At the end of this paper, numerical simulations on the free-floating space robot attitude control problems are given. And the results verify the effectiveness of Legendre pseudospectral method on solving the optimal attitude control problem.
Practice in Promoting Acta Metallurgica Siaica to High-Quality Journal
《金属学报》创办精品期刊的探索实践


中国科技期刊研究 , 2003,
Abstract: 介绍了《金属学报》(中文版)的现状和发展,详细阐述了本刊在坚持正确的办刊方向、科技为经济建设服务、切实提高期刊学术质量及保证期刊编辑出版质量、满足学术交流的需要等方面所做的努力。
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