一、 General Properties: 1.镧系元素从57号元素镧到第71号元素镥,共十五种元素,称为镧系元素,用Ln 表示。 2.稀土元素周期表B族中的钪(Sc)钇(Y)和镧系元素在性质上都非常相似并 在矿物中共生,由于镧系收缩,Y3+离子的半径落在Er3附近,Sc3离子的半径接近于 Lu3+,所以Sc、Y可以看作镧系元素的成员在化学上把Sc、Y和镧系元素统称为 稀土元素(rare earth's' elements),用RE表示

一、道路工程测量概述 路线勘测设计测量(route reconnaissance and design survey) 道路施工测量(road construction survey)

Background information your ho their potential The hyde school In 1966, Joseph W. Gauld founded the first Hyde school in Bath, Maine in response to a system of education which hebelieved was failing its children because of conflicting priorities. His search for a new approach in education led to a program that valued attitude over aptitude, effort over ability, and s

Try to find out all expressions showing graceful hands” in our text.How many times? Find out words of Mrs. Clark Pick out descriptions about ward and Mrs Clarks physical conditions

The hyde school In 1966, Joseph W. Gauld founded the first Hyde school in Bath, Maine in response to a system of education which hebelieved was failing its children because of conflicting priorities. His search for a new approach in education led to a program that valued attitude over aptitude, effort over ability, and s character over talent

Helpful Information Telecommunications Optical fiber( the medium and the technology associated with the transmission of information as light pulses along a glass or plastic wire or fiber. Information age Information superhighway

What does a pathogen have to do? Infect (infest) a host Reproduce(replicate) itself Ensure that its progeny are transmitted to another host

Medical Virology Dept. of Medical Microbiology and Parasitology Shanghai Second Medical University Shanghai, China. E.mail:(xkguoshsmu.edu.cn)

Mycoplasmas a group of the smallest organisms that can be free living in nature, Pass bacterial filter and also grow on laboratory media. More than 80 species, belong to Mycoplasmatales of mollicute. 3 families can be divided:

Campylobacter Among the most widespread cause of infection in the world Cause both diarrheal and systemic diseases Campylobacter jejuni