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4、Find the molecular formula of a hydrocarbon as that effuses 0.872 times as fast as O2 through a small hole (at same temperature and pressure).
According to the passage, all of the following statements are true EXCEPT ______ .
A．The two strands making up DNA's double helix can find each other easily in a complex chemical mixture
B．Evolution has solved the problem of building a computer smaller than a speck of dust a long time before
C．DNA not only programs cells to replicate themselves but also instructs them how to assemble individual molecules into new materials
D．The read-head components for computer hard drives are constructed by means of the technology known as a molecular beam epitaxy
A.平衡热力学性质
B.结构动力学性质
C.平衡输运性质
D.电子结构
E.能带结构
F.分子轨道
A.Atomic 原子式
B.Distributed 分布式
C.Factored 因子式
D.Networked 网络式
E.Molecular 模块式
F.Structured 结构式
A.atomic 原子
B.Distributed 分布
C.Factored 因子
D.Networked 网络
E.Molecular 分子
F.Structure 结构
Part B (10 points)
You are going to read a list of headings and a text about what parents are supposed to do to guide their children into adulthood. Choose a heading from the list A—F that best fits the meaning of each numbered part of the text (41—45). The first and last paragraphs of the text are not numbered. There are two extra headings that you do net need to use. (10 points)
Glass, in one form. or another, has long been in noble service to humans. As one of the most widely used of manufactured materials, and certainly the most versatile, it can be as imposing as a telescope mirror the width of a tennis court or as small and simple as a marble rolling across dirt.
(41)______.
The uses of this adaptable material have been broadened dramatically by new technologies: glass fiber optics—more than eight million miles—carrying telephone and television signals across nations; glass ceramics serving as the nose cones of missiles and as crowns for teeth; tiny glass beads taking radiation doses inside the body to specific organs; even a new type of glass fashioned of nuclear waste in order to dispose of that unwanted material.
(42)______.
On the horizon are optical computers. These could store programs and process information by means of light—pulses from tiny lasers—rather than electrons. And the pulses would travel over glass fibers, not copper wire. These machines could function hundreds of times faster than today's electronic computers and hold vastly more information. Today fiber optics are used to obtain a clearer image of smaller and smaller objects than ever before—even bacterial viruses. Anew generation of optical instruments is emerging that can provide detailed imaging of the inner workings of cells. It is the surge in fiber optic use and in liquid crystal displays that has set the U.S. glass industry (a 16 billion dollar business employing some 150,000 workers) to building new plants to meet demand.
(43)______.
But not all the glass technology that touches our lives is ultra-modem. Consider the simple light bulb; at the turn of the century most light bulbs were hand blown, and the cost of one was equivalent to half a day's pay for the average worker. In effect, the invention of the ribbon machine by Coming in the 1920s lighted a nation. The price of a bulb plunged. Small wonder that the machine has been called one of the great mechanical achievements of all time. Yet it is very simple: a narrow ribbon of molten glass travels over a moving belt of steel in which there are holes. The glass sags through the holes and into waiting moulds. Puffs of compressed air then shape the glass. In this way, the envelope of a light bulb is made by a single machine at the rate of 66,000 an hour, as compared with 1,200 a day produced by a team of four glassblowers.
(44)______.
The secret of the versatility of glass lies in its interior structure. Although it is rigid, and thus like a solid, the atoms are arranged in a random disordered fashion, characteristic of a liquid. In the melting process, the atoms in the raw materials are disturbed from their normal position in the molecular structure; before they can find their way back to crystalline arrangements the glass cools. This looseness in molecular structure gives the material what engineers call tremendous "formability" which allows technicians to tailor glass to whatever they need.
(45)______.
Today, scientists continue to experiment with new glass mixtures and building designers test their imaginations with applications of special types of glass. A London architect, Mike Davies, sees even more dramatic buildings using molecular chemistry. "Glass is the great building material of the future, the 'dynamic skin'", he said". Think of glass that has been treated to react to electric currents go
A、具有很好的吸附选择性It has good adsorption selectivity
B、如用于脱水的3Å、4Å分子筛For example, 3A and 4A molecular sieves used for dehydration
C、3Å分子筛：只允许H2O（2.3-3.1Å）、CH4等直径小于3Å的分子进入孔道（不吸附C2+烃）3A molecular sieve: only H2O (2.3-3.1a), CH4 and other molecules with diameter less than 3A are allowed to enter the pore (C2+ hydrocarbon is not adsorbed)
D、4Å分子筛：只允许H2O（2.3-3.1Å）、CH4 、 C2H6 等小于4Å的分子进入孔道（不吸附C3+烃）4A molecular sieve: only H2O (2.3-3.1a), CH4, C2H6 and other molecules less than 4A are allowed to enter the pore (C3+ hydrocarbon is not adsorbed)
E、3Å、4Å分子筛有利于从烃类气体中选择性吸收水分，而5Å则允许各种直链烷烃进入孔道吸附，故用于脱水选择性较差。 Molecular sieves 3A and 4A are favorable for selective absorption of water from hydrocarbon gases, while 5A allow various straight-chain alkanes to enter channels for adsorption, so they are less selective for dehydration.
F、具有很高的吸附性能It has high adsorption properties
G、很低的水汽分压，高温、高气体线速度等较苛刻条件下，仍保持较高的湿容量（其内部比表面积600～1000m2/g，大于一般吸附剂）。Low partial pressure of water vapor, high temperature, high gas linear velocity and other harsh conditions, still maintain a high wet capacity (its internal specific surface area of 600 ~ 1000m2/g, greater than the general adsorbent)
H、湿容量随温度变化小，在较高温度下仍有高吸附能力，实际使用时虽然经过反复再生，仍可以基本保持不变。The moisture capacity changes little with the temperature, and it still has a high adsorption capacity at a higher temperature. In practical use, it can remain basically unchanged despite repeated regeneration.
I、具有很高的脱水能力，对天然气水露点可降至-98℃，适用于天然气深冷法轻烃回收与液化前深度脱水。It has a very high dehydration capacity, and the dew point of natural gas water can be reduced to -98℃, which is suitable for deep dehydration before natural gas cryogenic light hydrocarbon recovery and liquefaction.
A.find / -type f \（-perm -4000 -o -perm -2000 \）–ls
B.find / -type f\(-perm -2000 –o –perm -4000\）–ls
C.find / -type f \（-perm -5000 -o -perm -2000 \）–ls
D.find / -type f\(-perm -4000 –o –perm -5000\）–ls
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