一种新型红光敏感光交联体系

研究了Oxonol在不同溶剂中的吸收和荧光光谱,观察到反常的溶致变色行为.研究了由Oxonol和双 (三氯甲基)三腈化合物所组成体系在不同环境中的光诱导电子转移生酸反应和其褪色效应,发现这一体系可在红光照射下灵敏地引发某些预聚物而发生光交联反应.对Oxonol在胶束体系中的荧光发射进行了研究,比较了它们的荧光量子产率,并对出现这种现象的原因进行了初步讨论.     

酵素菌肥的金属元素营养分析

在磷酸根、硅酸根存在下以2％硝酸镧作机体改进剂,测定了酵素菌肥中多种金属元素的含量,各元素的平均回收率分别为：K98．69％,Ca100.37%,Mg97．81％,Na96．06％,Cu98．26％,Fe96．45％,Zn99．78％,Sr93．54％,Li94．22％。方法简便,快速可靠,肯定 酵素菌肥的金属元素营养价值。     

Quantum Chemical Investigations on the Structures,Stabilities, Decompositions of Trinitrobenzenes,Their Chloro Derivatives

he molecular geometries, heats of formation, electronic structures of three trinitrobenzenes(1,2,3-TNB, 1,2,4-TNB, 1,3,5-TNB), their chloro derivatives were studied by using the quantum chemical MO AM1 method at the RHF level, ab initio method at the HF/3-21G level. The decompositions of the title compounds were investigated by using the AM1 method at the UHF level. The decomposition activation energies were obtained, the order of the relative stabilities of the title compounds is found. The substituent effects on the structures, properties, on the decompositions of the title compounds are discussed in the present paper.     

硝酸甲与硝酸乙酯的结构、振动频率和热力学性质的密度函数 理论(DFT)研究

用密度函数理论(DFT)的BLYP和B3LYP方法,取6-31G,6-31G^*,6-31G^*^*,6-311G,6-311G^*和6-311G^*^*六种基组,对硝酸甲酯和硝酸乙酯的几何构型和红外振动频率进行了计算研究.结果表明,B3LYP方法在采用极化基组(6-31G^*,6-31G^*^*,6-311G^*和6-311G^*^*)时计算得到的结果均较好,适用于硝酸酯类化合物的研究.而BLYP方法无论采用何种基组均不适用;运用校正后的B3LYP/6-31G^*频率(校正因子0.975)计算得到的热力学性质(C^o~p,H^o和S^o)与实验结果较吻合。     

Substituent Effect on Infrared Spectra and Thermodynamic Properties of Polynitroamino Substituted Cyclopentane and Cyclohexane

运用密度泛函理论方法计算并研究了多硝基氮杂取代环戊烷和环己烷中的取代基效应. 基于B3LYP/6-31G**水平优化的分子结构,通过简谐振动分析,求得两类单环硝胺的红外光谱并作归属,发现理论计算值与已有实验值吻合较好. 基于统计热力学原理,求得它们的热力学性质,探讨了热力学性质与温度和取代基数目之间的关系. 结果表明,热力学性质与温度变化和取代基数目之间均很好地线性相关,同时取代基数目对热力学性质的变化具有基团加和性     

聚环氧琥珀酸阻硫酸钙垢机理的分子动力学模拟

在不同温度不同水分子环境中对聚环氧琥珀酸(PESA)阻垢剂与硬石膏晶体主要生长面(001)的相互作用进行了分子动力学模拟. 结果表明：在323～343 K时,不同水分子数中PESA都能有效阻止CaSO₄垢的生长;同一水分子数中,不同温度下的结合能比较接近. 体系的结合能主要由库仑能变(包括离子键)提供,硬石膏晶体中的Ca原子与PESA中的羰基O原子发生了成键作用. PESA中羧基O原子和水分子中H原子之间存在氢键作用,而范德华相互作用有助于该PESA-H₂O-CaCO₃相互作用体系的形成. O(PESA的羧基)-H(H₂O)、O(CaSO₄)-H(H₂O)和O(CaSO₄)-H(PESA)原子对的径向分布函数表明,溶剂分子对聚环氧琥珀酸阻硫酸钙的阻垢性能有影响.     

“稳态对比法”测量不良导体的导热系数

以稳态法的实验装置为基础,通过调节加热源的电压保证待测样品及标样的散热盘的散热温度(电压)相同,记下加热盘和散热盘的温度(电压),根据傅里叶导热方程,以及标准样品的导热系数直接获得待测样品的导热系数.该方法避免了传统方法因散热盘散热过程的理论处理及数据读取引入的误差.     

Blood oxygen level-dependent MRI for the monitoring of neoadjuvant chemotherapy in breast carcinoma: initial experience

Purpose

To determine the feasibility of using R2? map MRI for pretreatment diagnosis and monitoring of tumor response to neoadjuvant chemotherapy (NAC) in patients with breast cancer.

Material and Methods

Twenty-eight women with breast cancer, as evidenced by pathology, underwent MR imaging prior to and after chemotherapy. All patients were examined by conventional MRI and R2? map imaging. Subjects were divided into major histological response (MHR) and non-major histological response (NMHR) groups. Mean R2? values of cancerous and normal glandular tissues were measured before and following NAC. Differences in R2? and ΔR2?% values between these two groups were compared with paired or independent t tests. The relationship between ΔR2?% and histological response was examined using Spearman's correlation test.

Results

Before NAC, the average R2? values in carcinoma were lower than in normal glandular tissue (P<.05). After two to four cycles of NAC, the R2? values in carcinoma were increased (P<.05 ), but this change was not significant in normal glandular tissue. After NAC, ΔR2?% was significantly higher in MHR as compared to NMHR (P<.05). The ΔR2?% correlated with the histological response (r=0.581, P<.01).

Conclusion

In women undergoing NAC for breast cancer treatment, R2? and ΔR2?% appear to provide predictive information of tumor response which is probably associated with changes in tumor angiogenesis and tissue oxygenation. R2? map imaging of breasts may therefore be useful in monitoring tumor response to NAC.     

最小费用流问题的一种改进算法

本用顶点表和弧表描述和存储最小费用流的参数，借助SQL语言的优点提出了一种求解最小费用流的简便算法。中提出了前沿节点和含潜弧的概念，并利用这些概念减少了最短路算法的迭代次数和每次迭代的计算量。最后给出了一个算例。     

具有边界摄动的拟线性Robin问题

A class of quasilinear Robin problems with boundary perturbation are considered. Under suitable conditions, using theory of differential inequalities the asymptotic behavior of solution for the boundary value problem is studied.