钻井液稀释剂单宁酸钾的研究与应用

介绍了钻井液稀释剂单宁酸钾的制备方法,对该稀释剂在钻井液中的性能进行了评定,探讨了单宁酸钾的稀释和防塌机理。室内与现场试验结果表明,单宁酸钾是一种性能优良的防塌稀释剂。     

Type inference with non-structural subtyping

We present an O(n³) time type inference algorithm for a type system with a largest type, a smallest type , and the usual ordering between function types. The algorithm infers type annotations of least shape, and it works equally well for recursive types. For the problem of typability, our algorithm is simpler than the one of Kozen, Palsberg, and Schwartzbach for type inferencewithout . This may be surprising, especially because the system with is strictly more powerful.     

Learning Line Features in 3D Geometry

Feature detection in geometric datasets is a fundamental tool for solving shape matching problems such as partial symmetry detection. Traditional techniques usually employ a priori models such as crease lines that are unspecific to the actual application. Our paper examines the idea of learning geometric features. We introduce a formal model for a class of linear feature constellations based on a Markov chain model and propose a novel, efficient algorithm for detecting a large number of features simultaneously. After a short user‐guided training stage, in which one or a few example lines are sketched directly onto the input data, our algorithm automatically finds all pieces of geometry similar to the marked areas. In particular, the algorithm is able recognize larger classes of semantically similar but geometrically varying features, which is very difficult using unsupervised techniques. In a number of experiments, we apply our technique to point cloud data from 3D scanners. The algorithm is able to detect features with very low rates of false positives and negatives and to recognize broader classes of similar geometry (such as “windows” in a building scan) even from few training examples, thereby significantly improving over previous unsupervised techniques.     

On the correctness of the Krivine machine

We provide a short proof of the correctness of the Krivine machine by showing how it simulates weak head reduction.     

一类特殊型行列式及其应用

给出了Ｖａｎｄｅｒｍｏｎｄｅ行列式的一类特殊型行列式的计算公式及其应用。进一步完善了Ｖａｎｄｅｒｍｏｎｄｅ行列式的理论，并加宽了应用范围。     

Towards an evaluation framework for knowledge management systems

In this paper we develop an evaluation framework for Knowledge Management Systems (KMS). The framework builds on the theoretical foundations underlying organizational Knowledge Management (KM) to identify key KM activities and the KMS capabilities required to support each activity. These capabilities are then used to form a benchmark for evaluating KMS. Organizations selecting KMS can use the framework to identify gaps and overlaps in the extent to which the capabilities provided and utilized by their current KMS portfolio meet the KM needs of the organization. Other applications of the framework are also discussed.

Local dynamics and stability of apocytochrome b562 examined by hydrogen exchange

Cytochrome b562 is a heme-binding protein consisting of four helices folded into a classic helix bundle motif. Though retaining much of the topology of the holoprotein, apocytochrome b562 displays physical features commonly associated with so-called protein molten globules. Here, the stability and dynamics of this "structured" molten globule are probed by examination of the dependence of its hydrogen exchange behavior upon the presence of a chemical denaturant. Compared to other systems studied in this manner, apocytochrome b562 displays a limited dynamic range of hydrogen exchange rates and the analysis required the development of a quantitative approach. The protein is found to have three regions of subglobal cooperative stability. The most stable region, or core, is composed of the central two helices of the bundle, with the N- and C-terminal helices being of independent and lower stability. The dependence of the global unfolding free energy upon denaturant concentration indicates the applicability of a binding model and explains the observed difference between global unfolding free energies obtained by the linear extrapolation method and those obtained by calorimetry and hydrogen exchange. These observations place a significant restraint upon the type of folding pathway that is operative for this protein and suggest that that the N- and C-terminal helices fold and unfold independently of the core of the molecule.     

RSView32和MATLAB之间的通讯

MATLAB是一种具有强大的矩阵处理功能和绘图功能的应用软件。在许多复杂工程应用中，需要将MATLAB和其他软件交互协同工作。本文介绍了MATLAB与罗克韦尔公司的RSView32的特点，并重点论述了他们之间的通讯方法。