绿色能源,世纪工程--西气东输工程

西气东输工程是国家实施西部大开发战略的重要举措.在鄂尔多斯盆地和塔里木盆地进行的大规模天然气勘探工作表明,可以为西气东输工程准备较为充分的天然气可采储量.同时,根据对河南、安徽、江苏、浙江和上海等五省市天然气需求的预测,天然气需求市场的形势良好.西气东输工程是中国境内第一条达到国际标准的大口径、高压力、长距离输气管道.通过技术攻关和高新技术的应用,西气东输工程从管材及制管、焊接、内涂敷、压缩机增压系统优化、自动化控制到流量计量和焊接的无损检测技术等方面都取得了突破性进展.西气东输工程跨越多个自然环境区和地质构造区带,在工程可行性研究中就环境保护和地质灾害的预防做了大量的研究工作,提出了一系列的保护和预防措施.     

广州市南沙区万顷沙网河区排涝调蓄演算研究

快速城市化进程改变了城市地区原有下垫面,不透水层面积增加,暴雨期间汇流时间缩短,洪峰流量加大,进而导致城市内涝加剧,严重影响城市的防洪安全.本研究以广州市南沙区万顷沙网河区为研究对象,基于水量平衡的调蓄演算方法,对研究区域蓄排设施的规模进行分析;构建MIKE11一维网河模型,对涝区水情进行模拟,校核排涝工程规模,并对工...     

Low-angle reflectivity modeling of land clutter

In this letter, a practical mean reflectivity model of radar land clutter (LC) for the complex system design of ground-based radars involved in low-angle targets on some typical terrains is studied using the inductive reasoning method. The functional relationships between the radar parameters and radar surface clutter backscattering are analyzed. Following the recent research work in the area of reflectivity modeling of LC in the literature, the least squares method is employed to estimate the model parameters. The model is validated using reliable practical data and shown to outperform other models in accuracy.     

Research on Autonomous Orbit Determination of Navigation Satellite Based on Crosslink Range and Orientation Parameters Constraining

Introduction Thepotentialvulnerabilityofsatellitenaviga tionsystemthatreliesongroundstationsisthat thesystemwouldbreakdownifgroundstations weredestroyed,whichcannotmeettherequire mentofnavigationwarfare[1].Withthedevelop mentofsuchspace basedsystemsasgrou…     

Contributions of individual variation in temperature, solar radiation and precipitation to crop yield in the North China Plain, 1961–2003

An understanding of the relative impacts of the changes in climate variables on crop yield can help develop effective adaptation strategies to cope with climate change. This study was conducted to investigate the effects of the interannual variability and trends in temperature, solar radiation and precipitation during 1961–2003 on wheat and maize yields in a double cropping system at Beijing and Zhengzhou in the North China Plain (NCP), and to examine the relative contributions of each climate variable in isolation. 129 climate scenarios consisting of all the combinations of these climate variables were constructed. Each scenario contained 43 years of observed values of one variable, combined with values of the other two variables from each individual year repeated 43 times. The Agricultural Production Systems Simulator (APSIM) was used to simulate crop yields using the ensemble of generated climate scenarios. The results showed that the warming trend during the study period did not have significant impact on wheat yield potential at both sites, and only had significant negative impact on maize yield potential at Beijing. This is in contrast with previous results on effect of warming. The decreasing trend in solar radiation had a much greater impact on simulated yields of both wheat and maize crops, causing a significant reduction in potential yield of wheat and maize at Beijing. Although decreasing trends in rainfed yield of both simulated wheat and maize were found, the substantial interannual variability of precipitation made the trends less prominent.     

北衙红色粘土型金矿地质特征和成矿条件

本文系统研究了北衙红色粘土型金矿的地质特征和矿床类型，并从金矿产出的地质背景入手，分析其形成条件，认为是本区很有代表性的一种新的金矿类型，对矿区增储和区域找矿具有重大意义。     

Ruthenium-ion-catalyzed oxidation of asphaltenes and oil-source correlation of heavy oils from the Lunnan and Tahe oilfields in the Tarim Basin, NW China

The identification of marine source rocks in the Tarim Basin is debated vigorously. The intention of this paper is to investigate the asphahenes in heavy oils from the Lunnan and Tabe oilfields and Well TD2 with ruthenium-ions-catalyzed oxidation technique (RICO), in order to explore its role in oil-oil and oil-source correlations, The RICO products included n-alkanoic acids, α,ω-di-n-alkanoic acids, branched alkanoic acids, tricyclic terpanoic acids, hopanoic acids, gammacerane carboxylic acid , regular sterane carboxylic acids and 4-methylsterane carboxylic acids. The n-alkyl chains and biomarkers bounded on the asphaltenes were of unsusceptibility to biodegradation. The distribution and absolute concentrations of n-alkanoic acids in the RICO products of heavy oils from the Lunnan and Tabe oilfields are different from those of Well TD2. The biomarkers bounded on the asphahenes, especially steranes, have a distribution trend similar to that of the counterparts in saturates. The sterane carboxylic acids and 4-methylsterane carboxylic acids in the RICO products of heavy oils from the Lunnan and Tahe oilfields, dominated by C30 sterane and C31 4-methylsterane carboxylic acids, respectively, are significantly different from those of the heavy oils of Well TD2, whose dominating sterane and 4-methylsterane carboxylic acids are C28 sterane and C29 4-methylsterane acids, respectively. The RICO products of the asphaltenes further indicate that the Middle-Upper Ordovician may be the main source rocks for heavy oils from the Lunnan and Tabe oilfields.     

On the Carbon—Star Status of Five Stars in a New Carbon Star Catalog

We find that five sources listed in the new carbon star catalog are not really carbon-rich objects but oxygen-rich stars, because they all have the prominent 10μm silicate features in absorption and the 1612MHz OH maser emission or/and the SiO molecular features. These objects were considered as carbon stars in the catalog based only on their locations in the infrared two-color diagram. Therefore to use the infrared two-color diagram to distinguish carbon-rich stars from oxygenrich stars must be done with caution, because, in general, it has only a statistical meaning.     

缢蛏糖原磷酸化酶基因多态性与糖原含量的关联分析

为探究缢蛏糖原磷酸化酶基因(Sc-GPH)与糖原含量的关系,本研究克隆获得Sc-GPH cDNA全长,检测其在不同组织、不同月份的表达模式,并在Sc-GPH基因编码区筛选与糖原含量关联的SNP位点.结果表明,Sc-GPH cDNA全长为3963 bp,开放阅读框为2541 bp,编码846个氨基酸;氨基酸序列多重比对和系统发育树显示,缢蛏与欧洲大扇贝、虾夷扇贝、长牡蛎等贝类亲缘关系较近,而与哺乳类、甲壳类、昆虫类亲缘关系较远.实时荧光定量PCR结果显示,Sc-GPH在8个组织中均有表达,其中在外套膜和足中表达量最高(p<0.01),推测与其糖原存储能力有关;不同月份的缢蛏外套膜和足中,Sc-GPH在8月表达量最高,而此时糖原含量较低,说明Sc-GPH的表达可能受缢蛏生殖周期的影响.以缢蛏"甬乐1号"群体为实验材料,在Sc-GPH基因编码区筛选到4个与糖原含量相关SNP位点,其中c.930T>C位点在台州野生群体中得到进一步验证,该位点为高糖原缢蛏分子标记辅助选育提供了候选标记.