重离子放射治疗双微小展宽峰组合照射方法

在基于被动式束流配送系统的分层适形重离子治疗当中,需要利用微型脊形过滤器（mini ridge filter,mini-RF）将单能重离子束Bragg峰展宽为峰区近似高斯分布的微小展宽峰（mini spread-out Bragg peak,mini-SOBP）,从而达到减少照射分层数及照射时间的目的。采用较宽的mini-SOBP可以有效减少照射分层数,但会增大展宽Bragg峰（SOBP）远端剂量跌落距离,增加对靶区后方正常组织或危及器官的辐照剂量。这一问题可以通过双mini-SOBP的组合照射方法来解决。使用2种mini-RF对单能重离子束Bragg峰略微展宽得到2种半高宽（FWHM）且剂量分布近似高斯分布的mini-SOBP,通过基于放射生物学模型的剂量优化,证实了在SOBP平顶区按生物有效剂量均匀和物理吸收剂量均匀的展宽情况下,双mini-SOBP组合照射方法均可以在减少照射分层数的同时较大幅度地减小SOBP远端剂量跌落距离。In layer-stacking conformal heavy-ion therapy based on passive beam delivery system,it is necessary to minimize the layer numbers and reduce irradiation time for layer-stacking conformal heavy-ion therapy.Gaussian shaped mini spread-out Bragg peaks (mini-SOBP) were generated by mini ridge filters (mini-RF) for monoenergetic heavy ion beams.It is effective to minimize the layer number by using mini-SOBPs with the bigger full width at the half maximum (FWHM),but in this way the distal dose fall-off distance of a spread-out Bragg peak (SOBP) will be enlarged,increasing the radiation damage to normal tissue or organ at risk behind the target volume.This issue could be solved by using mini-SOBPs based combinatorial irradiation method.In this study,Gaussian shaped mini-SOBPs with two different FWHMs were generated by two different mini-RFs for monoenergetic heavy ion beams.Based on radiobiological model calculations and dose optimizations,the mini-SOBPs based combinatorial irradiation method was confirmed to reduce the distal dose fall-off distances of SOBPs while minimizing the layer numbers for layer-stacking conformal heavy-ion therapy.     

一类二阶抛物型方程初边值问题解的存在定理

本文研究了一类二阶非线性抛物型方程解的存在唯一性问题.利用非线性分析中的吸引盆理论和同胚理论,获得了相应的二阶非线性抛物型方程初边值问题解的大范围存在唯一性定理.     

全局极值定理的一个拓广

本文在有限维Ｈｉｌｂｅｒｔ空间上改进了全局极值定理并给出了改进后定理的某些应用．     

拓扑群在连续统上的膨胀作用

本文把一个同胚的膨胀作用推广到拓扑群的情形,并研究了有限生成离散群 的膨胀作用,得到了如下结果:Z×Z不能膨胀地作用在单位闭区间I上,而自由积 Z★Z可以膨胀地作用在I上.     

Complete fuzzy topological hyperfields and fuzzy multiplication in the fuzzy real lines

Recently E. Sanchez has given a necessary and sufficient condition for the existence of a solution of a fuzzy $\text{A 1 X = C}$, with 1 the extension of a given binary operation in the universe of discourse.Using many valued logic we generalize this result and get a characterization also of the cases if $\text{A 1 X = C}$ has only nearly a solution.Additionally, we consider fuzzy relation equations and get similar results.     

On extension of isometries in (F)-spaces

An (F)-spaceE is said to be locally midpoint constricted (in short, Imp-constricted) if there exists some>0 such thatD(A/2) <D(A) for every subsetA ofE with 0<D(A), whereD(A) denotes the diameter ofA. Our main result goes as follow: LetE be an Imp-constricted (F)-space andU an open connected subset ofE. Assume thatT:U F is an isometry (i.e., a distance-preserving map) which mapsU onto an open subset of the (F)-spaceF. ThenT can be extended to an affine homeomorphism fromE toF. Also, some other results about the question whether each isometry between two (F)-spaces is affine are obtained.     

Locally injective maps in O-minimal structures without poles are surjective

If is continuous and locally injective, then is in fact surjective and a homeomorphism, provided is definable in an o-minimal expansion without poles of the ordered additive group of real numbers; `without poles' means that every one-variable definable function is locally bounded. Some general properties of definable maps in o-minimal expansions of ordered abelian groups without poles are also established.

     

Automorphisms of manifolds and algebraic K-theory: I

We investigate the homotopy type of (M)/TOP(M), where M is a compact manifold, TOP(M) is the simplicial group of homeomorphisms of M which restrict to the identity on ∂M, and is the simplicial group of block homeomorphisms of M which restrict to the identity on ∂M. In the so-called topological concordance stable range of M, we obtain an expression in terms of the topological Whitehead spectrum of M. If M is smooth, we also investigate the homotopy type of (M)/DIFF(M); in the smooth concordance stable range of M, it has an expression in terms of the smooth Whitehead spectrum of M.     

On R∞ and Q∞-manifolds

We give a characterization of manifolds modeled on $\text{R}{}^{\mathrm{\infty }}\text{= dir lim}$ or $\text{R}{}^{\mathrm{n}}\text{Q}{}^{\mathrm{\infty }}\text{=dir lim Q}{}^{\mathrm{n}}$, where Q is the Hilbert cube, and elementary short proofs of the Open Embedding Theorem for these manifolds and the following theorem generalizing the Stability Theorem: Each fine homotopy equivalence between these manifolds is a near homeomorphism. Moreover we establish the Open Embedding Approximation Theorem.     

Fuzzy addition in the L-fuzzy real line

Under the hypothesis L is a chain, we construct a binary operation ⊕ on the L-fuzzy real line $\text{R}$(L) which reduces to the usual addition on $\text{R}$ if ⊕ is restricted to the embedded image of $\text{R}$ in $\text{R}$(L), which yields a partially ordered, abelian cancellation semigroup with identity, and which is jointly fuzzy continuous on $\text{R}$(L). We show ⊕ is unique, i.e. it is the only extension of addition to $\text{R}$(L) which is consistent. We study the relationship between ⊕ and other fuzzy continuous extensions of the usual addition. We also show that fuzzy translation is a weak fuzzy homeomorphism and, under certain conditions, a fuzzy homeomorphism.