铸铁孕育机理的探讨

铸铁孕育机理的探讨王春生，严密田丽（浙江大学）（佳木斯工学院）关键词：生核，热力学，孕育机理。０引言人们普遍接受的硅铁浓度不均匀孕育理论认为￣［１］硅铁孕育作用是通过形成局部富硅区和形成以ＣａＳ等硫化物为核心，ＳｉＯ＿２为外壳的晶核联合作用来实现的。...     

The Early Axiomatizations of Quantum Mechanics: Jordan, von Neumann and the Continuation of Hilbert's Program

Hilbert's axiomatization program of physical theories met an interesting challenge when it confronted the rise of quantum mechanics in the mid-twenties. The novelty of the mathematical apparatus of the then newly born theory was to be matched only by its substantial lack of any definite physical interpretation. The early attempts at axiomatization, which are described here, reflect all the difficulty of the task faced by Jordan, Hilbert, von Neumann and others. The role of von Neumann is examined in considerable detail as he can be viewed here as the most outstanding of Hilbert's heirs. Von Neumann, especially in his work devoted to the proof of the impossibility of hidden variables, not only continued Hilbert's program but pushed it to its very limits, blending axiomatic rigor and interpretative commitment. (Received September 9, 1999)     

26S蛋白酶体调控微管蛋白的降解

为了探究微管蛋白在植物细胞中的降解机制,本文利用微管解聚药物、蛋白酶体抑制剂MG132结合遗传学和分子生物学等体内体外研究技术发现微管蛋白TUA和TUB是通过泛素化/26S蛋白酶体途径降解的,同时在26S蛋白酶体调节亚基RPN10突变体rpn10-1的植株中,TUA的降解与野生型相比没有显著差别,但是TUB的降解在突变体中被严重削弱,使得TUB在突变体中过量积累.此外,在突变体中分别过量表达TUA和TUB,对转基因植株鉴定表明过量表达TUA促进突变体根的生长而过量表达TUB严重抑制了突变体的生长,说明在突变体中TUA/TUB的比例是失衡的,过量的TUB蛋白对植物的生长是不利的.以上结果表明,26S蛋白酶体可以调控微管蛋白TUA和TUB的降解,蛋白酶体调控亚基RPN10可以通过调控TUB的稳定性来影响植物的生长和发育.     

绥芬河三种经济鱼类的生物学特性研究

利用2009年9-10月及2010年5-6月在绥芬河干、支流采集标本,初步研究了高体鮈、拉氏和湖3种鱼类的生物学特性.结果表明:(1)高体鮈渔获物体长范围是48.0-137.0mm,体重范围是1.8-36.8g;拉氏标本渔获物体长范围是24.0-138.0 mm,体重范围是0.3-40.1g;湖渔获物体长范围是32.0-88.0 mm,体重范围是0.4-10.5 g;(2)高体鮈丰满度范围为0.96-2.45;拉氏丰满度范围为0.84-3.00;湖的丰满度则在1.16-2.23之间;(3)高体鮈和拉氏均由三个龄组组成,其中1龄和2龄为优势龄组,其相对多度分别为92.64%和97.44%;湖仅含两个年龄组;(4)三种鱼类均在1龄时生长速度最快,其体长的绝对生长速度分别为64.33mm/y(高体鮈)、41.46 mm/y(拉氏)和52.56 mm/y(湖);(2)体长与体重的关系式为:W=11.06×10-5L2.57(高体鮈),W=3.67×10-5L2.81(拉氏)和W=7.91×10-5L2.65(湖);(5)雌:雄性比分别为1.1◇1(高体鮈),0.75◇1(拉氏),0.48◇1(湖);最小性成熟年龄均为2龄;(6)高体鮈、拉氏的绝对繁殖力分别为4,270-7,200粒、1,679-2,610粒和2,264-2,871粒;相对繁殖力分别为514-1,019粒/g、156-193粒/g和282-485粒/g。     

A non‐Gaussian generalization of the Airline model for robust seasonal adjustment

In their seminal book Time Series Analysis: Forecasting and Control, Box and Jenkins (1976) introduce the Airline model, which is still routinely used for the modelling of economic seasonal time series. The Airline model is for a differenced time series (in levels and seasons) and constitutes a linear moving average of lagged Gaussian disturbances which depends on two coefficients and a fixed variance. In this paper a novel approach to seasonal adjustment is developed that is based on the Airline model and that accounts for outliers and breaks in time series. For this purpose we consider the canonical representation of the Airline model. It takes the model as a sum of trend, seasonal and irregular (unobserved) components which are uniquely identified as a result of the canonical decomposition. The resulting unobserved components time series model is extended by components that allow for outliers and breaks. When all components depend on Gaussian disturbances, the model can be cast in state space form and the Kalman filter can compute the exact log‐likelihood function. Related filtering and smoothing algorithms can be used to compute minimum mean squared error estimates of the unobserved components. However, the outlier and break components typically rely on heavy‐tailed densities such as the t or the mixture of normals. For this class of non‐Gaussian models, Monte Carlo simulation techniques will be used for estimation, signal extraction and seasonal adjustment. This robust approach to seasonal adjustment allows outliers to be accounted for, while keeping the underlying structures that are currently used to aid reporting of economic time series data. Copyright © 2006 John Wiley & Sons, Ltd.     

WebDAV及其在Web群件系统中的应用

WebDAV协议是HTTP/1.1的扩展,定义了在Web的基础上支持群件应用的新方法.本文介绍了WebDAV的核心特性并用两个例子显示这些新方法的执行过程。最后,描述基于WebDAV的群件系统的基本功能和结构。