Geochemistry and possible origin of petroleum in Palaeozoic reservoirs from Halahatang Depression

The Halahatang Depression in the Tabei Uplift of the Tarim basin is an active exploration area because it has substantial reservoir potential and contains or is near to many commercial oil fields. Geochemical analysis indicates that Halahatang oils were derived from marine carbonate source rocks deposited under anoxic reducing conditions. The maturities for Halahatang oils are corresponding to the peak of the oil window and slightly higher than the neighboring Tahe oils. The Halahatang oils feature low Pr/Ph, C₂₁/C₂₃ tricyclic terpane and, C₂₈/C₂₉ sterane ratios, high C₂₉/C₃₀ hopane and C₃₅/C₃₄ hopane ratios, a “V” shape in the distribution of C₂₇–C₂₈–C₂₉ steranes and light carbon isotope ratios, similar to the Tahe oils and correlate well with the Middle-Upper Ordovician source rock. However, some source-related biomarker parameters imply a more reducing source organofacies with more zooplanktonic contribution than that for the Tahe oils.     

Chemistry of carbon rich star IRAS 15194-5115

We have constructed two gas-phase models to study the chemistry of circumstellar envelope surrounding the carbon-rich variable star IRAS 15194-5115. The network used consists of 3893 reactions involving 397 gas-phase species. The derived fractional abundances for many molecules are in excellent agreement with values obtained from observations. The predicted column densities from the two models go well with the observed values of carbon star IRC + 10216. The dominant formation routes for three groups of species are discussed through the inner and outer envelopes.     

The specific molecular identification of life experiment (SMILE)

We describe a compact, highly integrated instrument concept for the detection and identification of a wide range of molecules associated with extinct/extant life or potential life processes. The Specific Molecular Identification of Life Experiment (SMILE) will be sensitive to the presence of a range of target molecules using both electrical and optical transduction techniques, and incorporates molecular imprinted polymers in addition to traditional biological receptors such as antibodies. A number of versions of the concept are possible depending on available resources e.g. mass, volume, etc. The full concept utilises a novel imaging interferometer where a large number of molecular receptors are deposited on the measurement plane of an imaging interferometer and read out by an imaging detector, enabling multiple targets—biomarkers—within a sample to be measured simultaneously. The optics can also form the basis of an UV-NIR imaging Fourier spectrometer allowing basic mineralogy studies to be conducted using optical properties to assist in the determination of the geological context of the samples. By incorporating micro-fabricated transducer arrays, micro-fluidics and artificial molecular recognition systems, as well as recombinant antibody technology with appropriate integration methods, SMILE forms a compact and robust “Life Marker Chip” which has been proposed for future planetary missions including ESA's ExoMars mission, where the instrument offers the possibility of conducting a direct in situ search for signs of past or present biological activity on Mars. In addition to its role in planetary exploration, derivatives of SMILE have multiple terrestrial applications in fields such as forensic analysis and environmental monitoring.     

New approaches to the modelling of surface chemistry on interstellar grains

In recent years, the need to replace rate equations for studying grain-surface chemistry in the modelling of interstellar clouds has become apparent. In this article, we discuss the three new replacement methods that have been suggested to date, and contrast their relative strengths and weaknesses. This revised version was published online in July 2006 with corrections to the Cover Date.     

温度和盐度对短节硬毛藻(Chaetomorpha brachygona Harvey)生长发育的影响研究

利用双因素实验和单藻培养等方法,对采自广东南澳岛的短节硬毛藻(Chaetomorpha brachygona Harvey)进行研究,在不同温度和盐度条件下,对该硬毛藻的生长、活力以及形态进行了观察与测定。结果表明,温度和盐度对短节硬毛藻的生长均有一定影响,当温度为20°C时,藻体培养第3、6和12天活力分别为0.70—0.75Y、0.60—0.70Y和0.55—0.65Y,培养12天时藻体有生殖细胞形成,此温度有利于藻体维持活力;温度为25—30°C时,培养第3天时会大量形成生殖细胞;在盐度10、20、40和50时,藻体的生长与温度相关,即30°C25°C20°C;在盐度20—30时,藻体长度最大达4.55 cm;在盐度10—30时,更有利于藻体生长,整体趋势为2030104050。因此,实验条件下,温度25—30°C、盐度10—30更利于短节硬毛藻的生长和形成生殖细胞。本实验表明,短节硬毛藻为暖水、广盐性种,有可能在我国南方海区大量生长并扩散,具有引发绿潮的潜力。     

POLYMER CHARGE AND MOLECULAR WEIGHT EFFECTS ON TREATED IRRIGATION FURROW PROCESSES

lINTRODUCTIONFurrowirrigationsupplieswatertotheheadofindividuallyformedsoilchannelsataratethatmatchesorexceedsfurrowinfiltrationcapacity,sothatwateradvancesdownslopethroughthefieldtothefurrowoutflow.Increasinginflowrateincreasesstreamdepth,wettedperimeter,velocity,andfurrow-streamadvancerate.Thisincreasesinfiltrationandimprovesirrigationapplicationuniformity.However,boostinginflowsalsoincreasesthestream-shydraulicshearandsoildetachmentrate,andsedimentconcentration,transport,andfieldlosses…     

Chemical evolution of circumstellar matter around young stellar objects

Recent observational studies of the chemical composition of circumstellar matter around both high- and low-mass young stellar objects are reviewed. The molecular abundances are found to be a strong function of evolutionary state, but not of system mass or luminosity. The data are discussed with reference to recent theoretical models.     

CepheusA的C~（18）O（J＝1—0）分子辐射

利用日本名古屋大学天体物理系的毫米波射电望远镜对ＣｅｐｈｅｕｓＡ的Ｃ１８Ｏ（Ｊ＝１—０）分子辐射进行了观测．得到了它的谱线频谱图、强度分布图、速度分段积分等高图和位置速度图，并且得到了核区的有关参数．     

Molecular shocks in star forming regions

The role of excited molecular hydrogen as a powerful observational tool is examined in the context of shock phenomena in molecular clouds, particularly in star forming regions. Conclusions that may be drawn from line intensities and line profiles, and the properties of J and C shocks in a bow shock structure are discussed.     

Post‐Synthesis of Ti‐SBA‐15 in Supercritical CO2‐Ethanol Solution

Ti‐SBA‐15 materials with Ti incorporated into the framework of SBA‐15 and controllable Ti contents were successfully prepared via a post‐treatment route in supercritical CO₂‐ethanol solution, followed by calcination. The resultant Ti‐SBA‐15 materials were characterized by means of different techniques including X‐ray diffraction, X‐ray photoelectron spectroscopy, transmission electron microscopy, IR analysis, and N₂ sorption analysis. It was demonstrated that the resultant materials retained a structure similar to that of the parent SBA‐15, and Ti was incorporated into the framework of SBA‐15. At high Ti content, i.e, Si/Ti = 5:1, a TiO₂ phase formed and was coated onto the inner surface of SBA‐15 in addition to the incorporation of the Ti in the framework. The BET surface areas of the Ti‐SBA‐15 samples decreased with increasing Ti content. The presence of small amounts of H₂O in the reaction medium may have resulted in some TiO₂ nanoparticles being uniformly distributed in the pores of the SBA‐15 accompanying the incorporation of Ti in the SBA‐15 framework.