期刊文献+
共找到7篇文章
< 1 >
每页显示 20 50 100
伽玛刀的分代特征与选购要点 被引量:1
1
作者 韩俊庆 刘奇 曲凤声 《中国医疗器械杂志》 CAS 2010年第2期117-122,共6页
随着计算机技术的飞跃发展和放射治疗设备的不断更新,最新一代的伽玛刀放射治疗系统与最初的伽玛刀放射治疗系统已有巨大地显著区别。不仅在功能上不断完善,而且治疗的适应证也在不断扩展,突破了肿瘤外科的许多手术禁区,挽救了大批因解... 随着计算机技术的飞跃发展和放射治疗设备的不断更新,最新一代的伽玛刀放射治疗系统与最初的伽玛刀放射治疗系统已有巨大地显著区别。不仅在功能上不断完善,而且治疗的适应证也在不断扩展,突破了肿瘤外科的许多手术禁区,挽救了大批因解剖关系而不能进行手术治疗的肿瘤病人,其中也包括了部分良性病变的患者。但是时至今日,仍有许多学者对伽玛刀放射治疗系统的诸多功能和分代特征并不十分清楚,再加上各生产厂家对外宣传的不同引导,致使伽玛刀放射治疗系统的许多概念和分代特征存在着混乱,特别是在购置该治疗设备时更是显得无所适从。为此,笔者就近年来各厂家生产的伽玛刀放射治疗系统的特征作以综述,其目的是给各购置单位和专家提供部分可供参考的依据。 展开更多
关键词 伽玛刀 分代特征 选购要点
下载PDF
PARALLEL REGION PRESERVING MULTISECTION METHOD FOR SOLVING GENERALIZED EIGENPROBLEM 被引量:1
2
作者 曾岚 周树荃 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第2期51+46-50,共6页
The parallel multisection method for solving algebraic eigenproblem has been presented in recent years with the development of the parallel computers, but all the research work is limited in standard eigenproblems of ... The parallel multisection method for solving algebraic eigenproblem has been presented in recent years with the development of the parallel computers, but all the research work is limited in standard eigenproblems of symmetric tridiagonal matrix. The multisection method for solving the generalized eigenproblem applied significantly in many science and engineering domains has not been studied. The parallel region preserving multisection method (PRM for short) for solving generalized eigenproblems of large sparse and real symmetric matrix is presented in this paper. This method not only retains the advantages of the conventional determinant search method (DS for short), but also overcomes its disadvantages such as leaking roots and disconvergence. We have tested the method on the YH 1 vector computer, and compared it with the parallel region preserving determinant search method the parallel region preserving bisection method (PRB for short). The numerical results show that PRM has a higher speed up, for instance, it attains the speed up of 7.7 when the scale of the problem is 2 114 and the eigenpair found is 3, and PRM is superior to PRB when the scale of the problem is large. 展开更多
关键词 parallel processing structural analysis numerical algebra generalized eigenproblem parallel multisection method
下载PDF
Geochemical Characteristics of REE in Jurassic Coal of Yan'an Formation from Dongsheng Coalfield 被引量:1
3
作者 赵峰华 丛志远 +2 位作者 彭苏萍 唐跃刚 任德贻 《Journal of China University of Mining and Technology》 2002年第2期138-142,共5页
Concentrations of rare earth elements (REE) in Jurassic coal of YanAn Formation from Dongsheng coalfield located in the northeast of Ordos basin were determined by instrumental neutron activation analysis (INAA). Curv... Concentrations of rare earth elements (REE) in Jurassic coal of YanAn Formation from Dongsheng coalfield located in the northeast of Ordos basin were determined by instrumental neutron activation analysis (INAA). Curves of distribution pattern of REE were drawn, and many geochemical parameters were calculated. The result shows that 1) The contents of REE in Jurassic coal with low ash and sulfur are lower than those of Carboniferous and Permian coal from the Basin of North China; 2) Inside the Dongsheng coalfield, coal from the north has higher contents of REE than that form the south because the north is near the area of source rock which is the main supplier of REE, while the south is far away from the area of source rocks; 3) Although Jurassic coal in Dongsheng is the low ash coal with less than 10%, the contents of REE are still proportional to ash yield of ash and SiO 2 contents. 4) Although the Jurassic coal in Dongsheng were deposited in oxidative continental environment of river lake, Eu depletion of REE in coal commonly exists, and positive abnormity of Ce dose not exist. This reflects the REE distribution pattern of REE in source rock of continental area; and 5) Compared with other rocks, coal shows extremely complexity of distribution pattern of REE, which is the result of continuous alteration and redistribution of matter in coal occurred in open basin system. 展开更多
关键词 rare earth elements GEOCHEMISTRY Jurassic coal Dongsheng coalfield
下载PDF
Two-order Hermite vector-interpolating subdivision schemes
4
作者 FAN Min KANG Bao-sheng ZHAO Hua 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2006年第9期1566-1571,共6页
A family of two-order Hermite vector-interpolating subdivision schemes is proposed and its convergence and con- tinuity are analyzed. The iterative level can be estimated for given error. The sufficient conditions of ... A family of two-order Hermite vector-interpolating subdivision schemes is proposed and its convergence and con- tinuity are analyzed. The iterative level can be estimated for given error. The sufficient conditions of C2 continuity are proved. Geometric features of subdivision curves, such as line segments, cusps and inflection points, are obtained by appending some conditions to initial vectorial Hermite sequence. An algorithm is presented for generating geometric features. For an initial se- quence of two-order Hermite elements from unit circle, the numerical error of the 4th subdivided level is O(10?4). 展开更多
关键词 Two-order vectorial Hermite element Hermite-interpolating subdivision schemes Geometric features
下载PDF
The Research of Fractal Characteristics of the Electrocardiogram in a Real Time Mode
5
作者 Valery Antonov Anatoly Kovalenko +1 位作者 Artem Zagaynov Vu Van Quang 《Journal of Mathematics and System Science》 2012年第3期191-195,共5页
The article presents the results of recent investigations into Holter monitoring of ECG, using non-linear analysis methods. This paper discusses one of the modern methods of time series analysis--a method of determini... The article presents the results of recent investigations into Holter monitoring of ECG, using non-linear analysis methods. This paper discusses one of the modern methods of time series analysis--a method of deterministic chaos theory. It involves the transition from study of the characteristics of the signal to the investigation of metric (and probabilistic) properties of the reconstructed attractor of the signal. It is shown that one of the most precise characteristics of the functional state of biological systems is the dynamical trend of correlation dimension and entropy of the reconstructed attractor. On the basis of this it is suggested that a complex programming apparatus be created for calculating these characteristics on line. A similar programming product is being created now with the support of RFBR. The first results of the working program, its adjustment, and further development, are also considered in the article. 展开更多
关键词 Holter monitoring ECG correlation dimension fractal analysis of time series non-linear dynamics of heart rate
下载PDF
A SEMI-OPEN-LOOP CODING MODE SELECTION ALGORITHM BASED ON EFM AND SELECTED AMR-WB+ FEATURES
6
作者 Hong Ying Zhao Shenghui Kuang Jingming 《Journal of Electronics(China)》 2009年第2期274-278,共5页
To solve the problems of the AMR-WB+(Extended Adaptive Multi-Rate-WideBand) semi-open-loop coding mode selection algorithm,features for ACELP(Algebraic Code Excited Linear Prediction) and TCX(Transform Coded eXcitatio... To solve the problems of the AMR-WB+(Extended Adaptive Multi-Rate-WideBand) semi-open-loop coding mode selection algorithm,features for ACELP(Algebraic Code Excited Linear Prediction) and TCX(Transform Coded eXcitation) classification are investigated.11 classifying features in the AMR-WB+ codec are selected and 2 novel classifying features,i.e.,EFM(Energy Flatness Measurement) and stdEFM(standard deviation of EFM),are proposed.Consequently,a novel semi-open-loop mode selection algorithm based on EFM and selected AMR-WB+ features is proposed.The results of classifying test and listening test show that the performance of the novel algorithm is much better than that of the AMR-WB+ semi-open-loop coding mode selection algorithm. 展开更多
关键词 Speech/Audio Semi-open-loop coding mode selection Features selection Energy Flat-ness Measurement(EFM)
下载PDF
An efficient algorithm for factoring polynomials over algebraic extension field 被引量:1
7
作者 SUN Yao WANG DingKang 《Science China Mathematics》 SCIE 2013年第6期1155-1168,共14页
An efficient algorithm is proposed for factoring polynomials over an algebraic extension field defined by a polynomial ring modulo a maximal ideal. If the maximal ideal is given by its CrSbner basis, no extra Grbbner ... An efficient algorithm is proposed for factoring polynomials over an algebraic extension field defined by a polynomial ring modulo a maximal ideal. If the maximal ideal is given by its CrSbner basis, no extra Grbbner basis computation is needed for factoring a polynomial over this extension field. Nothing more than linear algebraic technique is used to get a characteristic polynomial of a generic linear map. Then this polynomial is factorized over the ground field. From its factors, the factorization of the polynomial over the extension field is obtained. The algorithm has been implemented in Magma and computer experiments indicate that it is very efficient, particularly for complicated examples. 展开更多
关键词 algorithm FACTORIZATION algebraic extension field
原文传递
上一页 1 下一页 到第
使用帮助 返回顶部