The effect of the rotating double-prism wide-angle laser beam scanner on the beam shape

In this paper, we describe a wide-angle laser beam scanner and the rigorous result of the wide-angle laser beam scanner was obtained with the help of the vector refraction theory. Using the rigorous results, the distortion of the beam shape was discussed. The distortion of the beam shape is varying with the different relative angles of the double prisms. According to the conservation of the energy, the distribution of the laser intensity is changed too. (c) 2005 Elsevier GmbH. All rights reserved.

Comparison of fluorescence spectra of Yb : Y3Al5O12 and Yb : YALO(3) single crystals

Yb:Y3Al5O12 (Yb:YAG) single crystals with Yb doping concentration 0.5 at.%, 5 at.%, 15 at.%, 25 at.%, 50 at.%, 100 at.% and Yb:YAlO3 (Yb:YAP) single crystals with Yb doping concentration 0.5 at.%, 5 at.%, 15 at.%, 30 at.% were grown by the Czochralski process. The fluorescence spectra of these crystals and the effects of self-absorption on the shape of the fluorescence spectra were studied. Through comparing the fluorescence spectra of Yb:YAG and Yb:YAP, all results indicate that the effects of self-absorption on the fluorescence spectra of Yb:YAP are remarkably stronger than that of Yb:YAG at the same Yb concentration. (c) 2006 Elsevier B.V. All rights reserved.

食蚊鱼鳃上台湾棘带吸虫囊蚴内种群的月变化

1993年7月—1994年6月,作者对食蚊鱼鳃上台湾棘带吸虫囊蚴内种群的变化进行了为期12个月的研究,结果表明:食蚊鱼种群数量和种群重量的月变化相似,但两者与水温没有相关性;食蚊鱼种群的体长结构呈季节性动态变化规律;食蚊鱼的感染与其自身的生长紧密相关,感染率、感染强度表现出了与体长相似的变化趋势;中间的两组鳃片寄生的囊蚴较多,不同鳃片组囊蚴平均密度的月变化规律一致,食蚊鱼任何两个鳃片组分布的台湾棘带吸虫囊蚴的平均数差异都显著(P<0.001);囊蚴在食蚊鱼鳃上的分布为聚集分布。

Molecular identification and expression analysis of natural resistance associated macrophage protein (Nramp) cDNA from Japanese flounder (Paralichthys olivaceus)

Natural resistance associated macrophage protein (Nramp) controls partially innate resistance to intracellular parasites. Its function is to enhance the ability of macrophages to kill pathogens. However, little is known about the structure and function of Nramp in lower vertebrates such as teleosts. We have recently isolated a cDNA encoding Nramp from Japanese flounder (Paratichthys olivaceus). The full-length cDNA of the Nramp is 3066 bp in length, including 224 bp 5' terminal UTR, 1662 bp encoding region and 1180 bp 3' terminal UTR. The 1662-nt open reading frame was found to code for a protein with 554 amino acid residues. Comparison of amino acid sequence indicated that Japanese flounder Nramp consists of 12 transmembrane (TM) domains. A consensus transport motif (CTM) containing 20 residues was observed between transmembrane domains 8 and 9. The deduced amino acid sequence of Japanese flounder had 77.30%, 82.71%, 82.67%, 79.64%, 80.72%, 90.97%, 91.16%, 60.14%, 71.48%, 61.69%, 72.37% identity with that of rainbow trout Nramp alpha and beta, channel catfish Nramp, fathead minnow Nramp, common carp Nramp, striped sea bass Nramp, red sea bream Nramp, mouse Nramp 1 and 2, human Nramp 1 and 2, respectively. RT-PCR indicated that Nramp transcripts were highly abundant in spleen, head kidney, abundant in intestine, liver and gill, and less abundant in heart. The level of Nramp mRNA in embryos gradually increases during embryogenesis from 4 h (8 cell stage) to 80 h (hatched stage) after fertilization. (c) 2005 Elsevier Ltd. All rights reserved.

GPP问题的骨架分析与启发式算法设计

图的划分问题(GPP)是具有广泛应用背景的典型NP-难解问题,高效启发式算法一直是该领域的研究热点.作为设计启发式算法的有力工具,GPP的骨架分析存在理论分析结果匮乏、骨架规模过小等缺陷.文中采用构造偏移GPP实例的技巧,不仅在理论卜证明了获取GPP的骨架是NP-难解的,并且利用一般GPP实例与偏移实例的关系,实现了骨架规模的提高.在此基础上,文中对于目前求解GPP问题最好的算法之一的IBS进行了改进,提出了基于偏移实例的IBS算法(BI-IBS).算法BI-IBS首先构造偏移GPP实例,然后再利用局部最优解交集对它进行归约,最后再求解归约后的规模更小的新实例.实验结果表明,BI-IBS比现有算法在解的质量上有了较显著的提高.文中的工作较完善地解决了GPP的骨架研究存在的问题,所采用的构造偏移实例的技巧对于其它NP-难解问题的骨架理论分析及启发式算法设计亦具有较高的参考价值.

结瘤固氮树种叶部主要养分迁移特征

结瘤固氮树种叶部主要养分迁移特征何兴元张成刚杨思河苏道岩张粤刘惠昌（中国科学院沈阳应用生态研究所，１１００１５）ＴｒａｎｓｐｏｒｔＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆＭａｉｎＮｕｔｒｉｅｎｔｓｉｎｔｈｅＬｅａｖｅｓｏｆＮｏｄｕｌａｔｅｄａｎｄＮｉｔｒｏ...

新型热塑性淀粉的制备和性能

以二甲基亚砜(DMSO)为增塑剂,通过熔融共混法制备了一种新型热塑性淀粉(TPS),研究不同增塑剂含量对材料结构和性能的影响,并与甘油及甘油/水复合增塑淀粉体系进行了比较.FTIR结果显示,DMSO能够与淀粉产生强烈而稳定的氢键相互作用.WAXD和SEM的研究结果表明,DMSO的加入破坏了淀粉的有序结构,实现了淀粉的塑化,形成均一的非晶连续相.同甘油及甘油/水增塑体系相比,DMSO与淀粉的羟基形成更为稳定的氢键,能够有效抑制淀粉的重结晶.动态力学和拉伸力学性能测试结果表明,经过DMSO的增塑,有效降低了淀粉的玻璃化转变温度,改善了材料的韧性,增塑效率要好于甘油及甘油/水复合增塑体系.

Synthesis of mesoporous LaPO4 nanostructures with controllable morphologies

Lanthanum phosphate (LaPO4) nanostructures with different morphologies were prepared by a facile solution-precipitation process. The effect of different reaction conditions on the morphology of nanostructures was studied. When the molar ratio of La3+:H3PO4 was around 1 : 2, 1 : 20, 1 : 100, and 1 : 200, four different morphologies, such as near-spherical, snowflake-like, star-shaped, lens-like nanostructures and short nanorods, were obtained, respectively. Meanwhile, similar shapes developed when the molar ratio of H3PO4 to ionic surfactants, such as SDS and CTAB, was varied. In addition, Eu3+ doped and Ce3+/Tb3+ co-doped LaPO4 nanostructures showed morphology evolution similar to undoped LaPO4 nanostructures. The optical properties of these doped LaPO4 were also characterized.