新型感可见光的光引发体系乙基曙红碘■盐的研究

合成并研究了新型感可见光的光引发体系乙基曙红碘盐。结果表明，该引发剂的物理化学性质和光敏引发效率受其结构、介质性质和浓度等诸多因素影响。在可见光照射下，发生由乙基曙红阴离子向二苯基碘阳离子的电子转移反应，产生具有引发活性的苯自由基和非活性的乙基曙红自由基。测定了光聚合的动力学方程以及聚合物的分子量和分子量分布。比较了曙红单碘盐和双碘盐的各种不同性质     

Polyisophthalamides with phenylsulfonyl pendent groups

A series of polyisophthalamides containing phenylsulfonyl groups was prepared from seven aromatic diamines and 5-phenylsulfonylisophthalic acid by the phosphorylation condensation method, and from 5-phenylsulfonylisophthaloyl chloride by the solution polycondensation method at low temperature. When compared to the analogous unmodified polyisophthalamides, the modified ones were found to be essentially amorphous, and they showed better solubility in organic solvents, and slightly higher glass transition temperatures. Thermogravimetric analysis showed that the polyisophthalamides containing pendent phenylsulfonyl groups have thermal stabilities similar to the unmodified ones. Mechanical strength of films and water sorption were also investigated. © 1993 John Wiley & Sons, Inc.     

Dynamics of arsenic speciation in surface waters: As(III) production by algae

Algae reduce and methylate arsenate [As(V)]. The end product of the overall transformation reaction can be arsenite [As(III)] or methylated arsenic. Field and laboratory data suggest a strong correlation between the end product of the reaction and the growth rate of the algae, with As(III) only produced during log (exponential, fast) growth. The result is a peak in As(III) concentration preceding or coincident with the algal bloom. This paper analyzes data from 18 different water bodies (five lakes, one river, six estuary/marine sites, six experimental sites). Algal blooms, As(III) peaks and algal blooms with preceding or coincident As(III) peaks were identified. In total, 80 algal blooms were identified, 49 (61%) of which were associated with As(III) peaks. In 78% of water bodies algal blooms were typically (>50%) associated with As(III) peaks. The average time lag between As(III) peaks and algal blooms was 20 days (standard deviation 18 days). Copyright © 2005 John Wiley & Sons, Ltd.     

新型晶体Nd:S-VAP激光特性研究

测量了 Nd:S-VAP[Nd:Sr₅(VO₄)₃F]晶体的吸收光谱特性,在583.0nm 和809.0nm处有强烈的吸收峰.用可调谐染料激光泵浦实现了低阈值、高效率的激光运转.在透射率15%的平-平腔情况下,斜率效率为50%,阈值2mJ,倍频绿光的中心波长为536.0nm,线宽为1.4nm.采用φ4mm×30mm 的氙灯泵浦,实现了自由运转和染料片调 Q 运转.阈值为130mJ,斜效率为1.3%.测量了不同腔长、不同染料片小信号透射率情况下的输出能量、脉冲宽度以及光束发散角和偏振特性等.     

β-环糊精与分散RGFL染料二元包络物研究

本文从 β-环糊精 (β- CD)与分散 RGFL染料包络反应的紫外 -可见光谱、二阶导数光谱和荧光光谱现象分析 ,得出 β- CD与 RGFL形成摩尔比为 1∶ 1包络物 ,包络物的平衡常数 Kf=1 .5× 1 0 3 L/mol。初步推测包络形成机制及包络物形式。     

Influence of root resistivity on plant water uptake mechanism,part I: numerical solution

The issue of water flow through the root zone of field crops represents a complex problem requiring knowledge of a large spectrum of phenomena from various disciplines. Although many investigations have been devoted to gain better understanding of water dynamics in the root zone, the problem is still insufficiently understood. The main objective of the presented work was to analyze the importance of root water resistivity in the plant water extraction process. The problem was solved numerically for a wide range of the soil–root conductivity ratio (SRCR). Two different types of root water uptake (RWU) mechanisms were obtained. The first one is related to low root resistivity or low SRCR, and, thus, exhibits a so-called “moving uptake front” (MUF) effect observed previously in several experimental studies. The second one is inherent in large values of root resistivity or high values of SRCR (larger than 10⁴), and is strongly dependent on the root density distribution. Deceased.     

Experimental determination of cw dye laser parameters by loss variation

The behavior of a cw dye laser under variation of the output coupling has been investigated. By studying the dependence of laser threshold, output power and slope efficiency on the degree of outcoupling, numerical values for macroscopic and microscopic laser parameters have been obtained. The macroscopic data comprise values for internal cavity losses and mode matching conditions, the microscopic data refer to molecular parameters of the dye used, such as cross-sections for stimulated emission and triplet-triplet absorption.     

超声波条件下降解染料废水的工艺条件研究

采用Fenton试剂对模拟染料废水的降解效果进行研究。结果表明,H2O2投加量、Fe2+投加量、pH值条件、超声处理时间的改变对染料废水的处理效果影响很大。对酸性染料:当pH为4.5,30%H2O2投加的体积分数为30mL/L,Fe2+投加的质量浓度为400mg/L,反应时间为40min时为降解反应的最佳操作条件。对碱性染料,正交试验表明当pH为4、30%H2O2投加的体积分数16mL/L、Fe2+投加的质量浓度为300mg/L、反应时间为60min时为降解反应的最佳操作条件,其降解率达98.46%,COD的去除率达到96.7%。     

Rh-B doped polymeric optical waveguide for integrated optics

A systematic study of fabrication and characterization of rhodamine-blue (Rh-B) doped polystyrene waveguide is presented. Optical absorption and mode effective refractive index measurement was performed on the waveguides fabricated on glass substrate prepared by dip coating technique. It is observed that doping of dye increase the index of refraction of waveguides. The losses, however, decrease initially for dye concentration upto 0.1% and thereafter increase rapidly.