埃洛石喇曼微探针光谱学研究

分布在新西兰马特里海湾的管柱状埃洛石矿物的喇曼光谱可通过Ｒｅｎｉｓｈａｗ１０００喇曼光谱显微镜系统获得。在完整波长范围内,利用喇曼微探针可获得直径仅８μｍ晶体的喇曼光谱,并可以研究光谱沿不同晶轴方向产生的特定振动。观测到的羟基衍生物的３个频带分别是３６１６．５ｃｍ＾－１、３．６２３．４ｃｍ＾－１和３６２９．７ｃｍ＾－１,３个频带与埃洛石八面体底部同界面内部烃基之间有密切联系。３６９８．２ｃｍ＾－１     

埃洛石的拉曼显微光谱

样品为新西兰Ｍａｔａｕｒｉ海湾产的管状埃洛石,利用Ｒｅｎｉｓｈａｗ１０００拉曼微系统摄得样品的拉曼光谱,由于该拉曼显微探头很小,因而所用样品的晶体直径仪０．８μｍ该光谱波长覆盖整个波长范围,激光可以沿不同轴线照射晶体,在羟基伸缩区域获得３６１６．５,３６２３．４及３６２９．７ｃｍ＾－１三个吸收峰,这三个峰归属于埃洛石八面体层共享的较低平面的内羟基振动,３６９８．２及３７０５ｃｍ＾－１吸收峰指定为未     

Impacts of diverted freshwater on dissolved organic matter and microbial communities in Barataria Bay, Louisiana, U.S.A

Here we present results of an initial assessment of the impacts of a water diversion event on the concentrations and chemical composition of dissolved organic matter (DOM) and bacterioplankton community composition in Barataria Bay, Louisiana U.S.A, an important estuary within the Mississippi River Delta complex. Concentrations and spectral properties of DOM, as reflected by UV/visible absorbance and fluorescence, were strikingly similar at 26 sites sampled along transects near two western and two eastern areas of Barataria Bay in July and September 2010. In September 2010, dissolved organic carbon (DOC) was significantly higher (568.1-1043 μM C, x=755.6+/-117.7 μM C, n=14) than in July 2010 (249.1-577.1 μM C, x=383.7+/-98.31 μM C, n=14); conversely, Abs254 was consistently higher at every site in July (0.105-0.314) than in September (0.080-0.221), averaging 0.24±0.06 in July and 0.15±0.04 in September. Fluorescence data via the fluorescence index (FI450/500) revealed that only 30% (8 of 26) of the July samples had an FI450/500 above 1.36, compared to 96% (25 of 26) for the September samples. This indicates a more terrestrial origin for the July DOM. Bacterioplankton from eastern sites differed in composition from bacterioplankon in western sites in July. These differences appeared to result from reduced salinities caused by the freshwater diversion. Bacterioplankton communities in September differed from those in July, but no spatial structure was observed. Thus, the trends in bacterioplankton and DOM were likely due to changes in water masses (e.g., input of Mississippi River water in July and a return to estuarine waters in September). Discharge of water from the Davis Pond Freshwater Diversion (DPFD) through Barataria Bay may have partially mitigated some adverse effects of the oil spill, inasmuch as DOM is concerned.     

Intrinsic bioremediation of a petroleum-impacted wetland

Following the 1994 San Jacinto River flood and oil spill in southeast Texas, a petroleum-contaminated wetland was reserved for a long-term research program to evaluate bioremediation as a viable spill response tool. The first phase of this program, presented in this paper, evaluated the intrinsic biodegradation of petroleum in the contaminated wetland. Sediment samples from six test plots were collected 11 times over an 11-month period to assess the temporal and spatial petroleum concentrations. Petroleum concentrations were evaluated using gas chromatography-mass spectrometer analyses of specific target compounds normalized to the conservative biological marker, C(30)17alpha,21beta(H)-hopane. The analyses of specific target compounds were able to characterize that significant petroleum biodegradation had occurred at the site over the one-year period. Total resolved saturate and total resolved aromatic hydrocarbon data indicated the petroleum was degraded more than 95%. In addition, first-order biodegradation rate constants were calculated for the hopane-normalized target compounds and supported expected biodegradation patterns. The rapid degradation rates of the petroleum hydrocarbons are attributed to conditions favorable to biodegradation. Elevated nutrient levels from the flood deposition and the unconsolidated nature of the freshly deposited sediment possibly provided a nutrient rich, oxic environment. Additionally, it is suggested that an active and capable microbial community was present due to prior exposure to petroleum. These factors provided an environment conducive for the rapid bioremediation of the petroleum in the contaminated wetland.     

Large-scale structure of molecular gas in Heiles Cloud 2: a remarkable rotating ring

We have mapped the J = 1 --> 0 transition of 13CO over a 3 deg2 region in Heiles Cloud 2 using the Five College Radio Astronomy Observatory 14 m telescope. The complete map contains 3600 individual spectra of which 2400 were sampled with 1' spacing. The map suggest that the structure of Heiles Cloud 2 is dominated by a quasi equilibrium rotating ring similar to those found in numerical calculations of the gravitational collapse of a rotating cloud. Within this ring, several dense condensations have been identified and partially mapped in C18O. These subcondensations, among which is the dense filament TMC-1, probably result from the instability of the ring to fragmentation and have masses on the order of the Jeans mass. Thus, they are marginally unstable to further collapse and may be the precursors of fragments that will eventually form stars.     

形成中的大陆壳

大陆地壳总成分是安山质的，这样的成分不可能通过现代地壳生长的主导方式即会聚边缘和板内玄开岩浆作用而产生。由此表明，太古代存在另一种不同的大陆壳产生方式，而且下地壳的拆沉作用可能是一种重要的循环作用。     

在计算合成震波图中震源和接收器井孔效果的组合

由于震源移入不同的地层及由于井孔环境的变化，井孔震源的辐射图形有很大变化，同样，地震检波器也有能够影响记录波形的接收图形。我们用两种方式将这些振幅和相位以合成震波图中。首先，由３－Ｄ有限并分的直接解为相对较小的地球模型提供精确的全波形解。对于震源／接收器大间距的模拟，我们将震源辐射的静止相位解与射线追踪的接收图形相结合。有限差分震波图与从均匀试验介质中计算出射线追踪结果的比较表明：根据射线计算出的     

Comet Sugano-Saigusa-Fujikawa (1983V)--a small, puzzling comet

Spectroscopic and infrared observations of Comet Sugano-Saigusa-Fujikawa (1983V) were obtained during its close approach to the Earth on 11-14 June 1983. The [O I] production rates of 1.8 +/- 0.9 x 10(26) atoms/s observed on 12.3 June and 7 +/- 3.5 x 10(26) atoms/s on 13.4 June lead to derived water-production rates of 3 x 10(27) mol/s on 12 June and 1.1 x 10(28) mol/s on 13 June. The abundances of the minor species NH2, CN, C2, and C3 are unusually low relative to [O I]. The upper limit to the average nuclear radius from our infrared and visual photometry on 12-13 June (assuming that the entire signal came from the nucleus) is approximately 370 m. The dust/gas mass ratio was <0.01 on June 12 and <0.005 on June 13.     

Proposed in situ secondary ion mass spectrometry on Mars

Secondary ion mass spectrometry is a powerful analytical tool, which has the potentiality, through molecular ion emission, of detecting minor phases, as well as the unique capability of directly measuring isotope abundances in mineral or organic phases without any prior physical, chemical or thermal processing. Applied to the in situ analysis of the Martian regolith, it can provide evidence of the presence of carbonates and, by inference (if carbonates constitute significant deposits), of past liquid water--a necessary condition for the development of life. In addition, oxygen isotopic composition of carbonates preserves a record of the temperature at which this phase precipitated and may therefore help decipher the past climatology of Mars. Detection of a carbon isotopic composition shift between carbonates and organic matter (on Earth, the result of a kinetic fractionation effect during photosynthesis) would provide a definite clue regarding the existence of a past biochemical activity on Mars.