三、任何厚度的同心球層所成的大气辐射在太阳大气的情况下的应用

在這個工作的第一段里,我求得對於任何厚度的球層大氣在表面上昏暗的定律,表为吸收與發射兩種係數的函數。這個公式比通常所用的多項式更要普遍一些,應用到太陽的情形,改進了日輪中心附近昏暗的計算法。第二段因討論到球面的曲率和輻射在這球層內的折射,對於星輪邊綠的影響,听引出的修改,我們討論了一般的情形和對於太陽辐射的特殊情形。這個修改數,即使在太陽的情形,也是不可忽略的,雖然折射的効應,因缺乏實驗的數據,尚难算出,可是球層的曲率的効應(純粹是一個幾何學上的问题),是可以算出的,縱然有時须得使用一些外插。我研究了這個効應對於表面層的溫度和在這些層裹的“能源函數”(fonction-source)的变化所生的影響。最後在第三段里,我舉出在里昂天文台使用的色度學的方法,對於太陽求出的色温度的結果,更用一種光譜法,證明赤道帶和極區有一種色温度的差異的存在,這差異是在第一方法里已經表示明白了的。     

Development and validation of biocriteria using benthic macroinvertebrates for North Carolina estuarine waters

Biological criteria were developed to assess water quality in mesohaline and polyhaline estuarine waters in North Carolina. The criteria used a combination of three metrics: a new 'Hilsenhoff-type' biotic index incorporating the sensitivity to pollution of each taxon and its relative abundance, total number of taxa, and number of amphipod and caridean shrimp taxa. Agreement with an independent data set was 90%, as was within site repeatability of this biocriteria over a range of water qualities and salinities. The versatility of the biotic index is discussed relative to other sampling methods and in other parts of the world.     

DNA adduct formation and DNA strand breaks in green-lipped mussels (Perna viridis) exposed to benzo[a]pyrene: dose- and time-dependent relationships

Green-lipped mussels, Perna viridis, were exposed to 0, 0.3, 3 and 30 micrograms l-1 (nominal concentrations) B[a]P under laboratory conditions over a period of 24 days. Mussels were collected on day 0, 1, 3, 6, 12, 18 and 24, and the levels of DNA adducts and DNA strand breaks in their hepatopancreas tissues monitored. Mussels exposed to 0.3 and 3 micrograms l-1 B[a]P showed marked increases in strand breaks after 1 day of exposure. DNA strand break levels in these mussels remained high and significantly different from the control values until day 3 for the 0.3 microgram l-1 treatment group, and day 6 for the 3 micrograms l-1 treatment group. This was followed by a gradual reduction in strand breaks. After 12 days, the levels of both groups had returned to the same level as that of the control. No increase in DNA strand breaks was observable in mussels exposed to 30 micrograms l-1 B[a]P in the first 12 days of exposure, but a significant increase was observed from day 12 to day 24. Increasing B[a]P concentrations resulted in elevated DNA adduct levels after 3-6 days of exposure, but this pattern of dose-related increase disappeared after 12 days. These results indicate that a better understanding of the complex interactions between exposure levels and durations is crucially important before DNA adduct levels and DNA strand breaks in P. viridis can be used as effective biomarkers for monitoring genotoxicants in marine waters.     

Measurement of a Peak in the Cosmic Microwave Background Power Spectrum from the North American Test Flight of Boomerang

We describe a measurement of the angular power spectrum of anisotropies in the cosmic microwave background (CMB) at scales of 0&fdg;3 to 5 degrees from the North American test flight of the Boomerang experiment. Boomerang is a balloon-borne telescope with a bolometric receiver designed to map CMB anisotropies on a long-duration balloon flight. During a 6 hr test flight of a prototype system in 1997, we mapped more than 200 deg(2) at high Galactic latitudes in two bands centered at 90 and 150 GHz with a resolution of 26&arcmin; and 16&farcm;5 FWHM, respectively. Analysis of the maps gives a power spectrum with a peak at angular scales of 1 degrees with an amplitude 70 μK(CMB).     

BeppoSAX and Chandra Observations of SAX J0103.2-7209 = 2E 0101.5-7225: A New Persistent 345 Second X-Ray Pulsar in the Small Magellanic Cloud

We present two weak lensing reconstructions of the nearby (zcl=0.055) merging cluster Abell 3667, based on observations taken approximately 1 yr apart under different seeing conditions. This is the lowest redshift cluster with a weak lensing mass reconstruction to date. The reproducibility of features in the two mass maps demonstrates that weak lensing studies of low-redshift clusters are feasible. These data constitute the first results from an X-ray luminosity-selected weak lensing survey of 19 low-redshift (z<0.1) southern clusters.     

Detection of Planetary Transits of the Star HD 209458 in the Hipparcos Data Set

A search of the Hipparcos satellite photometry data for the star HD 209458 reveals evidence for a planetary transit signature consistent with the planetary properties reported by Henry et al. and Charbonneau et al. and allows further refinement of the planet's orbital period. The long time baseline (about 2926 days or 830 periods) from the best Hipparcos transit-like event to the latest transit reported by Henry et al. for the night of 1999 November 15 (UT) allows for an orbital period determination of 3.524736 days with an uncertainty of 0.000045 days (3.9 s). The transit events observed by Charbonneau et al. fall at the interim times expected to within the errors of this newly derived period. A series of statistical tests was performed to assess the likelihood of these events occurring by chance. This was crucial given the ill-conditioned problem presented by the sparse sampling of the light curve and the non-Gaussian distribution of the points. Monte Carlo simulations using bootstrap methods with the actual Hipparcos HD 209458 data set indicate that the transit-like signals of the depth observed would only be produced by chance in 21 out of 1 million trials. The transit durations and depths obtained from the Hipparcos data are also consistent with those determined by Charbonneau et al. and Henry et al. within the limitations of the sampling intervals and photometric precision of the Hipparcos data.     

地震短期前兆

根据全球资料详细研究了各种地球物理和地球化学前兆的时问形式。对所用数据进行了统计分析。利用“卡帕平方”规律得出了前兆的时间形式和类型依赖关系的结论。讨论了成对相关系数计算的结果。     

甚年轻石笋的TIMS-230Th定年及其年层确定

自石笋微层古环境记录在我国于 １９９７年第一次报道以来,这一工作在国内迅速得到响应。但由于微层计时特性甚难确定,影响了这一工作的深入开展。研究表明,中国全新世石笋微层可大致分为南方型和北方型。１９９９年,谭明于中国云南宜良九乡溶洞风景区蝙蝠洞内采到一个接纳滴水正在生长的石笋(编号ＪＢＦ９９０１),高 １１０ｍｍ,顶部直径约 ４０ｍｍ,最大直径约 ７０ｍｍ。组成矿物主要为粉晶文石,白色微透明。石笋具有典型的中国南方型微生长层,即较厚的弱透光层与较薄的透光层互层旋回。同年,谭明又获得一个在１９９６年采于北京石花洞的正在生长石笋(编号ＬＳ９６０２),高１５５ｍｍ,最大直径８０ｍｍ,最小直径５０ｍｍ。     

TWO EPISODES OF MONAZITE CRYSTALLIZATION DURING METAMORPHISM AND CRUSTAL MELTING IN THE EVEREST REGION OF THE NEPALESE HIMALAYA

TWO EPISODES OF MONAZITE CRYSTALLIZATION DURING METAMORPHISM AND CRUSTAL MELTING IN THE EVEREST REGION OF THE NEPALESE HIMALAYA     

LONG TERM HISTORY (DEXTRAL TO SINISTRAL AND DUCTILE TO BRITTLE) OF THE DAMXUNG—JIALI SHEAR ZONE IN SOUTHERN TIBET

LONG TERM HISTORY (DEXTRAL TO SINISTRAL AND DUCTILE TO BRITTLE) OF THE DAMXUNG—JIALI SHEAR ZONE IN SOUTHERN TIBET