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Write down basic principles and applications of gas chromatography, high-performance liquid chromatography and capillary electrophoresis.

A、CE: separations of large organic species on the basis of their rate of migration through a medium under the effect of an electrical gradient, which is determined by the mass and charge of the species, the permeability of the supporting medium, and of course the magnitude of the electrical gradient. Hence species can often be separated on the basis of differences with regard to these characteristics. Better resolution than for similar HPLC separations can thus be obtained. Detection of the eluted components is typically achieved using detectors based on molecular spectrometry.

B、Gas chromatography: To provide the higher resolutions required by modern analyses, the use of long, small diameter capillary columns is the norm. Contemporary GC analysis of trace organic materials uses open tubular capillary columns where a liquid phase has been bound to the internal wall.

C、HPLC is almost exclusively performed in the reverse phase mode (RP-HPLC), using stationary phases of silica gel derivatised with silylated aliphatic hydrocarbons such as octasilyl (C-8) and octadecylsilyl (ODS) moieties. These are used in conjunction with mobile phases that are predominantly aqueous. HPLC is of most utility where the organic analytes have a large molecular mass, and hence have low volatility, and where the molecule is polar or contains many polar substituents.

D、Atomic absorption spectrometry (flame or electrothermal) (AAS, ET-AAS), atomic fluorescence spectrometry (AFS), inductively coupled plasma optical (or atomic) emission spectrometry (ICP-OES or ICP-AES), neutron activation analysis (NAA), X-ray fluorescence (XRF), proton-induced X-ray emission (PIXE), spark source or isotope dilution mass spectrometry (SSMS, IDMS), electrochemical (anodic stripping voltammetry and polarography) or inductively coupled plasma-mass spectrometry (ICP-MS).

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更多“Write down basic principles an…”相关的问题

第1题

Contents

Chapter One —— Basic elements: Principles and general framework

of German development policy........................1

Domestic conditions and development.................... 6

Basic criteria for German development policy

Chapter Two —— Priority concerns of German development policy:

Poverty, education, environmental protection............9

Poverty...................................11

Strategies for reducing poverty.... ................13

Education.................................18

Environmental protection and resource conservation..... ........33

Chapter Three —— Implementation of German development policy.

Organization, instruments and procedures ..............50

Bilateral German development assistance........... .......58

Financial cooperation........................63

Technical cooperation........................68

Manpower cooperation.................... .....71

Development assistance at EU level.................76

Multilateral development assistance....................81

From its contents' page, we know that the book mainly discusses

A．German development policy.

B．German rural development.

C．German development assistance.

D．German development agencies.

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第2题

What do Dr. Ravitchs basic principles of education center on?

A．All children should have access to an education of high quality.

B．Accountability and choice are very effective means.

C．More public services should be privatized at a faster speed.

D．Physical education isn"t an essential part of high-quality education.

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第3题

Please give brief introduction and make a comment on three Basic Principles of Berne Convention for the Protection of Literary and Artistic Works of 1886．(上海交大2007年研)

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第4题

1 Types of E-mail

2 University Courses—Basic Courses and Specialized Courses

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第5题

How to Remember: Some Basic Principles

How do you communicate something you've forgotten? You can't! Now's the time to fit memory into the communication picture. Don't be content with a 10 percent level of remembering. Tap into the following three basic laws and triple that figure. After all, improved memory means improved communication. THE PREREQUISITES

Most of us, psychologists say, don't use more than 10 percent of our native ability to remember. That's comparable to running a car on one or two cylinders and just poking along.

Why don't we use more of our inherent memory power? There are several answers. First, because we haven't been trained to. Nowhere in our schooling were we taught how to use our powers of memory. And second, because we often just don't care. And that leads me to the three things that I feel are essential to a more powerful memory.

First, you must have a burning desire to improve your memory. You must care about it. Most people struggle along with poor memories, enduring endless frustrations and embarrassments in their daily lives, because they just don't want to be bothered remembering the constant barrage of names, numbers, facts, and information. What you have to do is remind yourself of the many benefits of a good memory: the increased confidence I promised you, the popularity and the peace of mind. Aren't those three alone enough to stir a desire in you to improve?

The second prerequisite is the ability to concentrate. You will be effective in remembering to the degree that you are enough to concentrate. A short period of intense concentration will often enable you to accomplish more than years of dreaming.

The third prerequisite was revealed to me by former Postmaster-General James Farley of New York City. Mr. Farley was cited by associates for having the most remarkable memory in this century. I asked him his secret.

"There's no real secret," he said. "You simply must love people. If you do, you won't have any trouble remembering their names, and a lot more about them than that."

And that's the third essential: You must care about people. It wasn't long after I talked to Mr. Farley that I came across an interesting line from Alexander Pope. "How vast a memory has love," he wrote. Certainly a deeper interest in people, and in your work as well, should make your desire to remember and your concentration much easier.

THE BASIC LAWS

Visualize. Now you're ready to learn the basic techniques for developing your memory. The first essential is to visualize. Picture what you want to remember. Since 85 percent of all you learn and remember in life reaches you through your eyes, it is absolutely vital that you visualize the things you want to recall later. To do that, you must above all become aware. And awareness involves becoming both a keen observer and an active listener. You have to see clearly and hear accurately in order to picture vividly what you want to remember. Too many people go through life only partly awake, only partly aware. They don't forget names; they never hear them clearly in the first place. That art of retention is the art of attention.

Become curious, observant, and sensitive to everything around you. See the roof detail on that old building. Notice the difference between the tree greens of April and of August. Hear the difference between the sirens of an ambulance, a fire track, a police car. Sharpen your senses of sight and hearing -- they're the most important. Together, those two senses account for 95 percent of our memory power. Two ancient sayings highlight the importance of visualizing. "One time seeing is worth a thousand times hearing." And "A picture is worth ten thousand words."

Repeat. If school didn't bother to teach us formal memory work, it did teach us the need for repeating. We were taugh

A．Y

B．N

C．NG

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第6题

Three basic grouping of steps of L/C are not include （）.

A、issuance

B、purchase

C、examine and amendment

D、utilization

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第7题

Tired of Working in Your Country!

With over 500 instructors and 20 years of experience, we are the leader in the field of teaching foreign languages. We now have positions open in Osaka starting September/October 2004 for instructors of English, German, Spanish and French.

. Teach many different kinds of classes using the latest technology in small classes of up to 3 students.

. Accommodation (住宿), and other necessary documents (文件) will be ready before you leave.

. Applicants will teach their first language only.

. Excellent teacher training programs.

If you are young with a university degree and are willing to experience different cultures, apply (申请) now. Experience in teaching is an advantage but not specially required. Knowledge of the Japanese language is not necessary but good English skills and practical computer knowledge are basic requirements.

Apply with@C@V. and send letters to:

NOVA France, Mr. Sampy (IHT3/2)

34, Bd. Haussmann, 75009 Paris, France

Fax: 33148014804

Or visit our website: www. teadyp. Com.

The manager expects to meet and talk with successful applicants in Paris in June and July.

We know from the text that those who are going to Japan will ______.

A．teach English only in Osaka

B．receive a degree from a university

C．have free accommodation

D．get trained for the job

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第8题

With over 500 instructors and 20 years of experience, we are the leader in the field of teaching foreign languages. We now have positions open in Osaka starting September/October 2006 for instructors of English, German, Spanish and French.

Teach many different kinds of classes using the latest technology in small classes of up to 3 students.

.Accommodation (住宿), and other necessary documents (文件) will be ready before you leave.

.Applicants will teach their first language only.

.Excellent teacher training programs.

If you are young with a university degree and are willing to experience different cultures, apply now. Experience in teaching is an advantage but not specially required. Knowledge of the Japanese language is not necessary but good English skills and practical computer knowledge are basic requirements.

Apply with@C@V. and send letters to:

NOVA France, Mr. Sampy(IHT3/2)

34, B@D@Haussmann, 75009 Paris, France

Fax :33148014804

Or visit our website: www. teadyp, com

The manager expects to meet and talk with successful applicants in Paris in June and July.

What is the purpose of the text?

A．To introduce a language school in Japan.

B．To hire language teachers to work in Japan.

C．To describe working conditions in Japan.

D．To make clear the requirements for Japanese teachers.

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