精确放射治疗中改进的楔形挡板剂量修正算法

在精确放射治疗中,精确计算楔形挡板的楔形因子是精确修正加入楔形挡板后剂量值的关键。提出了基于衰减系数法思想的改进楔形野剂量修正算法,首先计算了楔形挡板材料的线性衰减系数,再根据楔形挡板的实际剖面尺寸,建立了线性拟合公式计算射线束穿过楔形挡板的实际厚度,精确计算楔形因子,并以AAPM55号报告提供的45°楔形挡板进行了验证。该方法在保证计算精度的同时减少了大量离轴测量数据,减轻了物理师的负担,可以作为一种有效的楔形挡板修正算法应用于放射治疗计划系统中。     

Heterogeneous “Organoclick” Derivatization of Polysaccharides: Photochemical Thiol‐ene Click Modification of Solid Cellulose

A simple and direct method for derivatization of solid polysaccharides is presented. The novel methodology is based on the combination of organic acid‐catalyzed esterification or etherification and photochemical thiol‐ene click derivatization of a heterogeneous polysaccharide. The solid cellulose was “organoclick” modified with aryl, alkyl and polyester groups, respectively. The modification allows for a highly modular and metal free surface modification of solid polysaccharides.

     

二维变量的主成分分析和回归分析的关系研究

对二维变量进行主成分分析相当于对坐标轴按某一角度进行旋转,而对其进行回归分析则可以求出与原坐标轴有夹角的回归直线,探讨了这两个角度之间的关系.结果表明,当二维变量间完全线性相关时,两个角度相等;若两者均在0～π/2范围内,则前者大于等于后者,若两者均在π/2～π范围内,则前者小于等于后者;两者不可能一个在0～π/2范围内,而另一个在π/2～π范围内.     

Synthesis, Characterization and Luminescence of Lanthanide Chloride Complexes with N,N,N'''',N''''-Tetra[(2-benzimidazolyl) methyl]-1,2-Ethanediamine

Imidazole groups play an important role in the coordination chemistry of the metal ions in many biological systems1. Earlier work has established its suitability for formations of binuclear copper1, iron2 and manganese3 complexes. Reaction of EDTB with Cu(H2O)6(BF4)2 in absolute ethanol has given a six-coordinate complex of [Cu(EDTB)](BF4)(BF3?O(C2H5)2)H2O4. Rare earth ions have similar physical and chemical properties with Ca2+ and Mg2+ which are important in biological systems. Wan…     

On Two-stage Estimate Based on Independent Estimate of Covariance Matrix

When an independent estimate of covariance matrix is available, we often prefer two-stage estimate （TSE）. Expressions of exact covarianee matrix of the TSE obtained by using all and some covariables in eovariance adjustment approach are given, and a necessary and sufficient condition for the TSE to be superior to the least square estimate and related large sample test is also established. Furthermore the TSE, by using some covariables, is expressed as weighted least square estimate. Basing on this fact, a necessary and sufficient condition for the TSE by using some covariables to be superior to the TSE by using all eovariables is obtained. These results give us some insight into the selection of covariables in the TSE and its application.     

Hamiltonian constants for several new entire solutions

Using the Hamiltonian identities and the corresponding Hamiltonian constants for entire solutions of elliptic partial differential equations, we investigate several new entire solutions whose existence were shown recently, and show interesting properties of the solutions such as formulas for contact angles at infinity of concentration curves.      

不动点集为F=U_(i=1)~mRP_i(1)×HP_i(n)的对合

(M,T)是一个在r维光滑闭流形M上的不平凡光滑对合,它的不动点集为F．本文给出了F=U(i=1)~m RPi(1)×HPi(n)时对合的协边类,其中HP(n)表示n维四元数射影空间．     

Kerberos协议的改进

以 Ｒ Ｓ Ａ 算法作为加密和签名工具，对 Ｋｅｒｂｅｒｏｓ 协议中票证和验证码的形式以及验证协议进行了改进，使整个验证过程更安全、可靠 在此基础上，通过在网络防火墙中增加网际验证服务器，实现了跨网络的远程安全访问方案     

Design and Synthesis of a Highly Stable Six-hydrogen-bonded Serfassembly Yellowish Green Electroluminescent Molecular Duplex

This paper describes the design, synthesis and characterization of a hydrogen-bonded molecular duplex with 1,8-naphthalimide fluorescent pendants. The two oligoamide molecular strands, with complementary hydrogen bond sequences of DDADAA and AADADD, can form an ultra stable self-assembly duplex. Its molecular structure was confu-med by ^1H NMR and ESI-MS, and its photoluminescence properties were determined. The resulting duplex exhibited a dramatically enhanced photoluminescence （PL） quantum efficiency of 63.7% compared to the corresponding 1,8-naphthalimide segment （32.4%）, suggesting that the formation of the duplex with larger molecular weight could successfully inhibit the quenching of the fluorescent pendant. This novel duplex is a prospective candidate for new electroluminescent emitter.     

Lepida Acid A from Basidiomycetes Russula lepida

RussulalepidaFr.hasbeenusedasfoodandmedicinalagentsinChina.Theextractofitsfruitingbodiesshowedanti-tumoractivity'.AspartofourstudyontheactiveprinciplesofhigherfungiinYunnan,weinvestigatedthechemicalconstituentsofR.lepidacollectedattheAilaoMountaininYurman.Thisreportdescribesthestructuralelucidationofanewcompound,lepidaacidAl,fromtheEtOHandCHC13-CH3OH(lfl)extractofthefruitingbodiesofR.lepida.ThechloroformfractionoftheEtOHandCHC13-CH3OH(lfi)extractfromthefruitingbodiesofR.lepidawassu…