C~(q+)和O~(q+)与原子碰撞的电子俘获过程的理论研究

在ECPSSR理论的基础上,利用OBKN近似描述电子俘获过程,得到了包括电子俘获过程贡献的ECPSSR理论,编写了相应的计算程序。采用该程序计算了不同电荷态离子与多种靶原子碰撞的电子俘获截面和相应的X射线产生截面,将计算得到的包含电子俘获过程贡献的X射线产生截面与实验结果进行了比较。对于具有满K壳层的入射离子碰撞,X射线产生截面与入射离子电荷态基本无关;对于以直接电离为主导的碰撞过程,计算得到的X射线产生截面与实验数据符合得很好;对于全裸和单K空穴入射离子的碰撞,计算高估了X射线产生截面。

1980-2000年中国LUCC对气候变化的响应

基于中国1980-2000年气候数据及两期土地利用／土地覆盖(LUCC)数据,利用Holdridge植被生态分区模型、重心模型及土地利用程度模型,分析气候变化及人类活动对中国植被覆盖及土地利用的影响程度及变化趋势。1980-2000年间,中国大部分地区温度升高,降水增多。气候变化不仅影响了中国植被群落分区,更进一步影响了植被群落的生长状况;东北、华北、内蒙古高原等区域未利用土地型向草地和灌木生态类型转换,草地和灌木型生态类型向林地和耕地型转换;又因为1980-2000年间中国经济的发展,东部沿海区域城市乡村建设用地及交通用地的增多,使土地利用类型南农业耕地型向建设用地型发展,导致土地利用程度指数的升高。气候变化及经济发展的双重作用,导致中国土地利用程度重心20年来向东北方向移动了54km,东西方向土地利用程度偏移强度,气候占81％,人类活动占19％,南北方向土地利用程度偏移强度,气候占85％,人类活动占15％。

一种解聚聚对苯二甲酸丙二醇酯废料的方法

一种温和解聚聚对苯二甲酸丙二醇酯的方法是以甲醇为解聚剂，将聚对苯二甲酸丙二醇酯与甲醇的重量比为１∶１－２０，解聚反应温度介于１５０－３００℃之间，压力为甲醇自生成压力，解聚时间为０．１－１０．０小时。聚对苯二甲酸丙二醇酯的废料解聚为对苯二甲酸二甲酯（ＤＭＴ）和１，３－丙二醇（ＰＤＯ）。本发明具有工艺流程简单、易于操作、定向生成单体产物ＤＭＴ和ＰＤＯ的优点。

THE APPLICATION OF AN ULTRAMICROELECTRODE IN HOMOGENEOUS CATALYTIC REACTION .1. GENERAL CHARACTERISTIC OF A HOMOGENEOUS CATALYTIC REACTION AT AN ULTRAMICROELECTRODE WITH ARBITRARY GEOMETRY UNDER STEADY-STATE

A general characteristic of the electrochemical process coupling with a homogeneous catalytic reaction at an ultramicroelectrode under steady state is described. It was found that the electrochemical process coupling with homogeneous catalytic reaction has a similar steady state voltammetric wave at an ultramicroelectrode with arbitrary geometry. A method of determination for the kinetic constant of homogeneous catalytic reaction at an ultramicroelectrode with arbitrary geometry is proposed.

THE VARIATION AND MOVEMENT OF A KIND OF EDDIES IN SHELF SLOPE WATER

Considering the characteristics of the time and space scales of the eddies we established a quasi-static and quasi-geostrophic model to describe their variation and movement in shelf slope water. The analytical solution revealed the main properties of the variation: slow expansion and fast stagnation processes and the law of the eddy motion affected under the background field. All theoretical results are proved by satellite image measurements.

平面运动的串联测量方法研究及其与并联方法的比较

提出了用于测量平面运动位姿的三自由度串联和并联测量方法,介绍了串联和并联测量方法的测量原理.通过建立串联测量方法的误差模型,得出了几何误差源与原始测量参数的映射关系和对末端位姿误差的影响情况,得到了这种方法的精度分析结果.仿真结果和试验数据证明了分析的正确性.同时,从几何误差源的产生和测量运动特性等方面对串联和并联测量方法进行了比较.

贵州平坝县白云岩风化壳中稀土元素分布特征之初步研究

本文报道了平坝白云岩风化剖面风化前缘稀土元素超常规富集（总量达3％以上）现象及其特征，并通过主元素，稀土元素的测定。结合白云岩中“酸不溶物”的提取和代表性样品的化学淋溶实验研究，讨论了白云岩风化壳剖面稀土元素的分异特征，认为风化前缘稀土元素的富集是由3方面的因素共同作用造成的：1）对白云岩风化残积的继承；2）剖面上部一部分轻稀土淋滤取积；3）碳酸盐岩中非均匀分布的原生含磷矿物风化产生的稀土磷酸盐矿物的聚集，后者是最重要的原因。

Emi2-mediated inhibition of E2-substrate ubiquitin transfer by the anaphase-promoting complex/cyclosome through a D-box-independent mechanism.

Vertebrate eggs are arrested at Metaphase II by Emi2, the meiotic anaphase-promoting complex/cyclosome (APC/C) inhibitor. Although the importance of Emi2 during oocyte maturation has been widely recognized and its regulation extensively studied, its mechanism of action remained elusive. Many APC/C inhibitors have been reported to act as pseudosubstrates, inhibiting the APC/C by preventing substrate binding. Here we show that a previously identified zinc-binding region is critical for the function of Emi2, whereas the D-box is largely dispensable. We further demonstrate that instead of acting through a "pseudosubstrate" mechanism as previously hypothesized, Emi2 can inhibit Cdc20-dependent activation of the APC/C substoichiometrically, blocking ubiquitin transfer from the ubiquitin-charged E2 to the substrate. These findings provide a novel mechanism of APC/C inhibition wherein the final step of ubiquitin transfer is targeted and raise the interesting possibility that APC/C is inhibited by Emi2 in a catalytic manner.

Early growth and adult respiratory function in men and women followed from the fetal period to adulthood

While some studies suggest that poor fetal growth rate, as indicated by lower birth weight, is associated with poor respiratory function in childhood, findings among adults remain inconsistent. A study was undertaken to determine the association between early growth and adult respiratory function.

Photo-double detachment from the F- ion

The correlated process of photodetaching two electrons from the F- ion following the absorption of a single photon has been investigated over an energy range 20-62 eV. In the experiment, a beam of photons from the Advanced Light Source was collinearly merged with a counter-propagating beam of F- ions from a sputter ion source. The F+ ions produced in the interaction region were detected, and the normalized signal was used to monitor the relative cross section for the double-detachment reaction. An absolute scale for the cross section was established by measuring the spatial overlap of the two beams and by determining the efficiency for collection and detection of the F+ ions. The measured cross section is compared with R-matrix and random phase approximation calculations. These calculations show that the Auger decay of the 2s2p(6) core-excited state of the F atom plays a minor role in the production of F+ ions and that double detachment is likely to be dominated by simultaneous correlated ejection of two valence electrons at energies well above threshold.

Chymotrypsin-like serine proteinases are involved in the maintenance of cell viability

An increasing number of studies have implicated serine proteinases in the development of apoptosis. In this study, we assessed the ability of a set of highly specific irreversible inhibitors (activity probes), incorporating an a-amino alkane diphenyl phosphonate moiety, to modulate cell death. In an initial assessment of the cellular toxicity of these activity probes, we discovered that one example, N-a-tetramethylrhodamine phenylalanine diphenylphosphonate {TMR-Phe^P(OPh)₂} caused a concentration-dependent decrease in the viability of HeLa and U251 mg cells. This reduced cell viability was associated with a time-dependent increase in caspase-3 activity, PARP cleavage and phosphatidylserine translocation, establishing apoptosis as the mechanism of cell death. SDS-PAGE analysis of cell lysates prepared from the HeLa cells treated with TMR-Phe^P(OPh)₂, revealed the presence of a fluorescent band of molecular weight 58 kDa. Given that we have previously reported on the use of this type of activity probe to reveal active proteolytic species, we believe that we have identified a chymotrypsin-like serine proteinase activity integral to the maintenance of cell viability.

3D Morphable Model Construction for Robust Ear and Face Recognition

Recent work suggests that the human ear varies significantly between different subjects and can be used for identification. In principle, therefore, using ears in addition to the face within a recognition system could improve accuracy and robustness, particularly for non-frontal views. The paper describes work that investigates this hypothesis using an approach based on the construction of a 3D morphable model of the head and ear. One issue with creating a model that includes the ear is that existing training datasets contain noise and partial occlusion. Rather than exclude these regions manually, a classifier has been developed which automates this process. When combined with a robust registration algorithm the resulting system enables full head morphable models to be constructed efficiently using less constrained datasets. The algorithm has been evaluated using registration consistency, model coverage and minimalism metrics, which together demonstrate the accuracy of the approach. To make it easier to build on this work, the source code has been made available online.