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发行人应依法与担保人签订担保合同，担保范围应包括可转换公司债券的本金及利息、违约金、损害赔偿金和()
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The author's analogy between the mail-sorting system and chemistry would be LESS accurate
Warm and diplomatic in manner, devoted to his wife and sons, Smith fits the stereotype of
The present economy remains dependent on a massive inward flow of
natural resources that includes vast amounts of non-renewable resources,
followed by a reverse flow of economically spent matter back to the ecosphere.
Line Chemical sustainability problems are determined largely by these economy-
(5) ecosphere material flows which current chemistry education essentially ignores,
such that it has become imperative for chemists to develop the technological
dimension of a sustainable civilization. Chemistry teachers should better
emphasize the effect of compositions, outcomes, and economics of chemical
processes on both human health and the ecosphere. There is one overarching
(10) scientific reason why chemical technology pollutes: chemists developing new
processes strive principally to achieve reactions through relatively simple
reagent designs by employing almost the entire periodic table to attain diverse
reactivity, while by contrast nature accomplishes a huge range of selective
biochemical processes through a reagent design much more elaborate than the
(15) aforementioned synthetic ones. Electric eels can store charge via concentration
gradients of biochemically common alkali metal ions across the membranes of
electroplaque cells, while synthetically-designed batteries used for storing
charges must make use of elements such as lead and cadmium. Given this
strategic difference, manmade technologies often distribute throughout the
(20) environment persistent pollutants that are toxic because they contain elements
that are used sparingly or not at all in biochemistry.
Imagine all of Earth's chemistry as a mail sorter's wall of letter slots in a
post office, with the network of compartments extending toward infinity, each
of which representing a separate chemistry so that, for example, thousands of
(25) compartments are associated with stratospheric chemistry or with a human cell.
An environmentally mobile persistent pollutant can move from compartment to
compartment, sampling a large number and finding those it can perturb, and
while many of these perturbations may be inconsequential, others can cause
unforeseen catastrophes, such as ozone holes or endocrine disruption in the
(30) human body. Most compartments remain unidentified, furthermore, giving
ample reason for scientific humility when considering the safety of persistent
mobile compounds.
There are several obstacles to overcome in achieving a sustainable
chemistry free of these mobile pollutants, the first being that of incorporating
(35) environmental considerations into decisions concerning the reactions and
technologies to be developed in the laboratory. It is equally critical that
chemistry that is not really green does not get sold as such, and that the public
is not misled with false or insufficient safety information. And since many
chemical sustainability goals such as those associated with solar energy
(40) conversion call for ambitious, highly creative research approaches, short-term
and myopic thinking must be avoided-after all, chemistry exerts a near
boundless influence on human action and is thus inext
Creating a relatively simple model of the known ecosystem requires a tremendous amount of
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