尼日尔三角洲油气分布特征

尼日尔三角洲是正在发展中的中、新生代大型三角洲,其主要烃源岩为阿卡塔组海相泥岩,主要储集岩为海陆交互相的阿格巴达组砂岩。盆地油气藏分布特征主要表现为:阿格巴达组沉积厚度大,储层发育,几乎储存了三角洲所有油气资源;圈闭类型多样,但以滚动背斜油气藏为主;油气藏几乎遍布整个三角洲,但主要集中在五个区带;阿格巴达组各砂组都含油气,但纵向上主要集中于浅中部;流体性质差异大,以普通轻油和挥发性油藏为主;油气藏规模普遍较小,但是产能高。     

巧妙隐藏邮件地址

最近作了一个Blog,为了让网友联系方便,特意在网页上留下了电子邮件地址。可是却发现垃圾邮件越来越多,原来很多邮件地址都是靠一种邮件地址收集器的软件自动搜索网页中如电子邮件格式字符串而得到的,所以会收到无穷无尽的垃圾邮件了。怎么避免这种情况呢?最近笔者发现的一款小     

轴承车床实用套状接料器设计

ＨＺＣ２０－Ｚ系列轴承专用自动车床采用的液压驱动、齿轮齿条传动的套状接料器具有制造简单，结构尺寸小，接料准确，寿命长和效率高等优点，并通过分析计算和实践应用验证了其设计的正确性。附图３幅，参考文献３篇。     

轴承在床实用套状接料器设计

ＨＺＣ２０－Ｚ系列轴承志自动车床采用的液压驱动，齿轮齿条传动的套状接料器具有制造简单，结构尺寸小，接料准确，寿命长和效率高等优点，并通过分析计算和实践应用验证了其设计的正确性。     

微区电阻测试方法及新测试仪研制

文章对国内外开展微区薄层电阻测试的方法进行了综述，特别对改进范德堡四探针技术方法的测试原理、测试过程与测试结果进行了论述与分析，对微区电阻测试方法的进一步发展提出了一种可操作的方法，并研制出新型四探针测试样机。     

短信平台移动QQ

“移动QQ”服务是腾讯科技有限公司与移动通信运营公司合作推出，使移动电话用户可以用短信功能、WAP功能和QQ用户进行短讯通信的一种服务。它与KJavaQQ相比，使用条件要相对简单点，不需要手机支持KJava，也不要求手机有上网功能，只要用户手机可以正常收发短信即可，这无疑为喜欢聊天而手机又不支持KJavaQQ的用户提供了很好的一种方式。要使用移动QQ也很简单，只需要有一部可正常收发中文短信的手机即可，如果你没有QQ号码，还可以用手机短信再申请一个QQ号码，并且短信平台的移动QQ使用起来与KJava相差无几。     

世界稠油开采现状及发展趋势

本文是根据１９９５年６月在加拿大卡加里召开的国际稠油研讨会以及同年１０月和次年３月在北京召开的中国石油天然气总公司稠油开发工作会和“九五”稠油开采新技术论证会等方面材料编写的综述文章。     

Detection of probe dither motion in near-field scanning optical microscopy

The probe-to-sample separation in near-field scanning optical microscopes can be regulated by a noncontact shear-force sensing technique. The technique requires the measurement of a minute dither motion applied to the probe. We have characterized an optical detection method for measuring this motion to determine the optimum detection configuration in terms of sensitivity and stability. A scalar diffraction model of the detection method is developed for calculating sensitivity, and experimental results are found to be in good agreement with the theoretical predictions. We find that maximum sensitivity and stability cannot be achieved simultaneously, and it may be desirable in practice to trade sensitivity for enhanced stability.     

Tunable single frequency thulium:YAG microchip laser with external feedback

By use of the reflection of an uncoated external etalon, a diode-pumped thulium-doped YAG microchip laser was forced into a single-frequency mode. The wavelength of the single-frequency radiation was tunable over 15 nm simply by translation of the etalon relative to the laser. Output powers of 45 mW were achieved in a monolithic setup that is insensitive to vibrations. The origin of the single-frequency oscillation is the wavelength-dependent reflection of the etalon, which is coupled back into the laser resonator. This method permits the combination of inherently stable, single-frequency resonator geometries such as microchips with laser materials that have broad tuning ranges.     

Molecular mechanism for the effects of trehalose on beta-hairpin folding revealed by molecular dynamics simulation

Recent work has shown that trehalose can facilitate and inhibit protein folding, but little is known about the molecular basis of these effects. Molecular-level insights into how the osmolyte affects protein folding are of significance for the rational design of small molecular additives for enhancing or hindering the folding of proteins. To investigate the molecular mechanisms of the facilitation and inhibition effects of trehalose on protein folding, molecular dynamics (MD) simulation of a beta-hairpin peptide (Trp-Arg-Tyr-Tyr-Glu-Ser-Ser-Leu-Glu-Pro-Glu-Pro-Asp) in different trehalose concentrations (0-0.26 mol/L) is performed using an all-atom model. It is found that at a proper trehalose concentration (0.065 mol/L), the peptide folds faster than that in water, but it cannot fold to the beta-hairpin at higher trehalose concentrations. Free energy landscape analysis indicates the presence of three intermediate states in both pure water and in 0.065 mol/L trehalose, but the potential energy barriers in the folding pathway decrease greatly in 0.065 mol/L trehalose, so the peptide folding is facilitated. Moreover, at this trehalose concentration, there is a favorable balance between the peptide backbone hydrogen bonds (H-bonds) and the peptide-trehalose H-bonds, leading to the stabilization of the folded peptide. At higher trehalose concentrations, however, trehalose molecules cluster in the peptide region and interact with the peptide via many H-bonds that prevent the peptide from folding to its native structure. The energy landscape analysis indicates that the potential energy barriers increase so greatly that the peptide cannot overcome it, getting trapped in a local free energy basin. The work reported herein has elucidated the molecular mechanism of the peptide folding in the presence of trehalose.