Spatial variability in water quality and surface sediment diatom assemblages in a complex lake basin,lake of the woods,ontario,canada

Lake of the Woods (LOW) is an international waterbody spanning the Canadian provinces of Ontario and Manitoba, and the U.S. state of Minnesota. In recent years, there has been a perception that water quality has deteriorated in northern regions of the lake, with all increase in the frequency and intensity of toxin-producing cyanobacterial blooms. However, given the lack of long-term data these trends are difficult to verify. As a first step, we examine spatial and seasonal patterns in water quality in this highly complex lake on the Canadian Shield. Further, we examine surface sediment diatom assemblages across multiple sites to determine if they track within-take differences in environmental conditions. Our results show that there are significant spatial patterns in water quality in LOW. Principal Component Analysis divides the lake into three geographic zones based primarily on algal nutrients (i.e., total phosphorus, TP), with the highest concentrations at sites proximal to Rainy River. This variation is closely tracked by sedimentary diatom assemblages, with [TP] explaining 43% of the variation in diatom assemblages across sites. The close correlation between water quality and the surface sediment diatom record indicate that paleoecological models could be used to provide data on the relative importance of natural and anthropogenic sources of nutrients to the lake.

小型气驱动式U形振荡水槽

本文介绍气驱动式U形振荡水楷(U形管)的设计特点、流场品质和初步实验结果。在结构设计上采用了理论计算的弯管型线、步进电机带动蝶阀的控制系统和吸气驱动等较先进的技术措施,使得该设备具有流场品质好、结构简单、调节方便等优点,是开展振荡流实验研究的基本设备。

用LDA测量U形水槽内的振荡流

本文介绍LDA用于测量U形水槽内的振荡流。水槽直管段为正方形,弯管段内侧弯面及外侧弯面是专门计算设计的。对于水平直管段、竖管段及弯管段共七个截面,测量了边界层外振荡流速的振幅分布。对于水平直管段上底面及下底面各三个截面,测量了边界层內振荡流速的振幅分布及相位分布。测量结果和无限长槽道的理论计算结果作了比较,二者基本符合。

物理力学讲义

border="0" alt="" width="109" height="150" align="left" />《物理力学讲义(新世纪版)》第1章绪论阐明了物力学的内容、观点和方法，第2、第3、第4章是基础原理，第5章到第9章分别处理气体、固体的液体的热力学性质，说明了从分子结构计算宏观性质的方法，第10章到第13章处理各种输运过程，像热传导、粘滞性、扩散、中子慢化及热辐射等。
《物理力学讲义(新世纪版)》的特点是给出了明确具体而切实可行的计算方法，使得工程介质和材料的热力学性质可以不完全依靠实验就能确定。
物理力学是一门新兴的学科，它从物质的微观结构出发。提供计算机工程技术和所用介质和材料的热力学性质的方法。

目录
第1章　绪论
1.1　什么是物理力学?
1.2　物质的结构
1.3　原子半径与分子结构
1.4　物质结构概念的应用
第2章　量子力学
2.1　薛定谔波动方程
2.2　振幅方程
2.3　波函数的物理意义
2.4　谐振子
2.5　点粒子的体系
2.6　氢原子
2.7 自由粒子
2.8　氢原子的内部动力学
2.9　类氢原子的能级
2.10　电子自旋
2.11　分子能级的分类
2.12　分子的波动方程
2.13　双原子分子
2.14　U(r)的性质
2.15　刚性线转子的简单势
2.16　莫尔斯势
2.17　多原子分子
第3章　统计力学基础
　3.1　体系的系集
　3.2　关于微观性质的准备知识
　3.3　一个系集状态的一般性质
　3.4　关于平均的规则
　3.5　一个经典系集的描写
　3.6　可及性(主要是经典部分)
　3.7　关于相似体系的系集的可及态对称群和反对称群
　3.8　关于真实系集本征函数的对称类型
　3.9　计算普通系集可及态的捷径
　3.10　关于定域系配容的计算
第4章　恒定体系系集的一般原理
　4.1　权重
　4.2　几个简单体系的状态的权重
　4.3　可及态(配容)的计算
　4.4　两组定域线性振子的系集
　4.5　最陡下降法的简单描述
　4.6　平均值和统计温标
　4.7　多自由度体系及退化体系
　4.8　线性谐振子
　4.9　二维及三维谐振子
　4.10　没有轴自旋的刚性转子
　4.11　有绕轴自旋的刚性转子(对称陀螺)
　4.12　两组非定域系组成的系集
　4.13　数学推导
　4.14　结果之摘要
　4.15　退化体系
　4.16　经典统计力学
　4.17　无结构质点在盒子中的运动
　4.18　系集的外作用力
　4.19　统计力学与热力学之间的关系
……
第5章　理想气体
第6章　固体的热学性质
第7章　固体的物态方程
第8章　非理想气体
第9章　液体和稠密气体
第10章　输运过程的一般理论
第11章　粘滞性，扩散和热传导
第12章　中子的扩散和减速
第13章　热辐射
附录　物理常数表
编后记

谈镐生文集

border="0" alt="" width="150" height="150" align="left" />本文集收入了著名力学家、应用数学家、中国科学院院士谈镐生先生在流体力学、稀薄气体动力学和应用数学研究领域的论文和研究报告26篇，谈镐生先生倡导和支持力学基础研究的有关文章和论述21篇，谈先生的学术活动和生活图片多幅，以及谈镐生先生生平，最后附有谈先生生平年表。

 

 

基于U形塑料光纤的氧气传感器

报道了一种基于荧光猝灭原理的光纤氧气传感器.采用塑料光纤作为传感和传光元件进行氧气传感,传感头制成U形.以邻菲咯啉钌作为荧光标记物,用溶胶-凝胶法制备敏感材料.采用相移法来实现对荧光寿命的测定.测量了不同弯曲半径传感头对氧气传感的灵敏度,发现当U形光纤的弯曲半径较小时系统的灵敏度较高.对荧光寿命和氧气浓度的关系进行了测量,发现二者呈亚线性关系,提出双荧光体模型解释这一实验现象.

基于U型塑料光纤和邻啡咯啉钌的溶解氧传感器

本文提出了一种基于U型塑料光纤和邻啡咯啉钌的溶解氧传感器。光纤传感头放在样品池中，测量了不同氮氧体积比情况下荧光强度和寿命。研究了邻啡咯啉钌的浓度、传感头的退火时间和U型光纤的弯曲半径对系统灵敏度的影响。我们提出了双层模型来解释实验结果不符合S-V方程的实验现象，并用双层模型分析了弯曲半径对系统灵敏度的影响。通过对溶解氧浓度和荧光寿命亚线性曲线的拟合，我们得出敏感层的厚度和S-V系数分别为0.59和0.61。

Identification and molecular cloning of a novel neuromedin U analog from the skin secretions of toad Bombina maxima

Amphibian skin contains rich neuropeptides. In the present study, a novel neuromedin U (NmU) analog was isolated from skin secretions of Chinese red belly Load Bombina maxima. Being 17-amino acids long, its primary structure was established as DSSGIVGRPFFLFRPRN-NH2, in which the C-terminal 8-residue segment (FFLFRPRN) is the same as that of rat NmU, while the N-terminal part DSSGIVGRP shows a great sequence variation compared with those of NmU peptides from different resources. The peptide, named Bm-NmU-17, was found to elicit concentration-dependent contractile effects on smooth muscle of rat uterus horns. The cDNA Structure of the peptide, as obtained by a 3'-RACE strategy and subsequently cloning from a skin cDNA library, was found to contain a coding region of 438 nucleotides. The encoded precursor is composed of 145 amino acids with a single copy of Bm-NmU-17 located towards the C-terminus. The sequence of the peptide is preceded by a dibasic site (Lys-Arg) and followed by the sequence of Gly-Arg-Lys, providing the sites of cleavage and releasing of the mature peptide. (c) 2005 Elsevier B.V. All rights reserved.

First-principles LDA plus U and GGA plus U study of neptunium dioxide

We have performed a systematic first-principles investigation to calculate the electronic structures, mechanical properties, and phonon-dispersion curves of NpO2. The local-density approximation+U and the generalized gradient approximation+U formalisms have been used to account for the strong on-site Coulomb repulsion among the localized Np 5f electrons. By choosing the Hubbard U parameter around 4 eV, the orbital occupancy characters of Np 5f and O 2p are in good agreement with recent experiments [A. Seibert, T. Gouder, and F. Huber, J. Nucl. Mater. 389, 470 (2009)]. Comparing to our previous study of ThO2, we note that stronger covalency exists in NpO2 due to the more localization behavior of 5f electrons of Np in line with the localization-delocalization trend exhibited by the actinides series.