月表有效太阳辐照度实时模型

月表太阳辐射是深入研究月表温度分布的关键问题之一.本文根据月表有效太阳辐照度与太阳常数、太阳辐射入射角以及日月距离之间的关系,建立月表有效太阳辐照度的实时模型.该模型在1950-2050年的100年内的理论误差百分比小于0.28%,相对前人提出的模型在精度上有了很大程度的提高,能较为真实地反映月表有效太阳辐照度随时间的变化规律.计算结果表明2007年月表太阳辐照度的年变化范围在1321.5-1416.6 W·m^-2之间,平均为1368.0 W·m^-2.通过对月表太阳辐射入射角计算结果的分析,证实了月球的两极可能存在极昼极夜.

贵州红枫湖水体溶解有机质的剖面特征和季节变化

溶解有机氮(dissolved organic nitrogen , DON) 与溶解有机碳(dissolved organic carbon , DOC) 相结合在湖泊水体溶解有机质(dissolved organic matter , DOM) 的研究中少有报道. 本研究对贵州喀斯特地区高原性湖泊-红枫湖水体DOC 和DON 的含量进行了近2a 的测定,研究了DOM 的剖面特征和季节变化,并探讨了DOM 垂向分布和季节变化的影响因素. 结果表明,红枫湖DOC 的浓度范围为1160～3108 mg·L - 1 ,DON 的浓度范围为0110～0137 mg·L - 1 . 在湖水混合期表层和底层的DOC和DON 的浓度基本一致,在湖水分层期DOC 和DON 浓度表现出从表层往底层减小的趋势. 表层水体(0～2m 或3m) DOC 的浓度在春末夏初或夏季达到最大,DON 的浓度在春末夏初稍高于其它月份. 结合叶绿素和降雨的数据分析认为,藻类活动和陆源输入直接导致了表层水体DOM 的季节变化模式. DOM 的C/ N 在一般情况下向下增大,但在夏季南湖的垂向水柱上,DOC 和DON 的浓度在12m 以下增大,C/ N 从12m 的1811 下降为14m 的1419 ,并向下持续减小,这很有可能是颗粒态有机质发生降解释放出C/ N 较低的DOM ,成为水体内DOM 的一个内源.

Characteristic infrared spectroscopic patterns in the protein bands of human breast cancer tissue

Infrared (IR) spectra of normal, hyperplasia, fibroadenoma and carcinoma tissues of human breast obtained from 96 patients have been determined and analyzed statistically. Several spectral differences were detected in the frequency regions of N-H stretching, amide I, II and III bands: (1) the bands in the region 3000-3600cm-1 shifted to lower frequencies for the carcinomatous tissue; (2) the A(3300)/A(3075) absorbance ratio was significantly higher for the fibroadenoma than for the other types of tissues; (3) the frequency of the a-helix amide I band decreased for the malignant tissue, while the corresponding beta -sheet amide I band frequency increased; (4) the A(1657)/A(1635) and A(1553)/A(1540) absorbance ratios were the highest for fibroadenoma and carcinoma tissues; (5) the A(1680)/A(1657) absorbance ratio decreased significantly in the order of normal > hyperplasia > fibroadenoma > carcinoma; (6) the A(1651)/A(1545) absorbance ratio increased slightly for the fibroadenoma and the carcinoma tissues; (7) the bands at 1204 and 1278 cm(-1), assigned to the vibrational modes of the collagen, did not appear in the original spectra as resolved peaks and were distinctly stronger in the deconvoluted spectra of the carcinoma tissue and (8) the A(1657)/A(1204) and A(1657)/A(1278) absorbance ratios, both yielding information on the relative content of collagen, increased in the order of normal < hyperplasia < carcinoma < fibroadenoma. The said differences imply that the information is useful for the diagnosis of breast cancer and malignant breast abnormalities, and may serve as a basis for further studies on conformational changes in tissue proteins during carcinogenesis. (C) 2001 Elsevier Science B.V. All rights reserved.