【医】 开链

[ noun ]
a chain of atoms in a molecule whose ends are not joined to form a ring
<noun.object>

Open \O"pen\, a. [AS. open; akin to D. open, OS. opan, G. offan,
Icel. opinn, Sw. ["o]ppen, Dan. aaben, and perh. to E. up.
Cf. {Up}, and {Ope}.]
1. Free of access; not shut up; not closed; affording
unobstructed ingress or egress; not impeding or preventing
passage; not locked up or covered over; -- applied to
passageways; as, an open door, window, road, etc.; also,
to inclosed structures or objects; as, open houses, boxes,
baskets, bottles, etc.; also, to means of communication or
approach by water or land; as, an open harbor or
roadstead.

Through the gate,
Wide open and unguarded, Satan passed. --Milton

Note: Also, figuratively, used of the ways of communication
of the mind, as by the senses; ready to hear, see,
etc.; as, to keep one's eyes and ears open.

His ears are open unto their cry. --Ps. xxxiv.
15.

2. Free to be used, enjoyed, visited, or the like; not
private; public; unrestricted in use; as, an open library,
museum, court, or other assembly; liable to the approach,
trespass, or attack of any one; unprotected; exposed.

If Demetrius . . . have a matter against any man,
the law is open and there are deputies. --Acts xix.
33.

The service that I truly did his life,
Hath left me open to all injuries. --Shak.

3. Free or cleared of obstruction to progress or to view;
accessible; as, an open tract; the open sea.

4. Not drawn together, closed, or contracted; extended;
expanded; as, an open hand; open arms; an open flower; an
open prospect.

Each, with open arms, embraced her chosen knight.
--Dryden.

5. Hence:
(a) Without reserve or false pretense; sincere;
characterized by sincerity; unfeigned; frank; also,
generous; liberal; bounteous; -- applied to personal
appearance, or character, and to the expression of
thought and feeling, etc.

With aspect open, shall erect his head. --Pope.

The Moor is of a free and open nature. --Shak.

The French are always open, familiar, and
talkative. --Addison.
(b) Not concealed or secret; not hidden or disguised;
exposed to view or to knowledge; revealed; apparent;
as, open schemes or plans; open shame or guilt; open
source code.
[1913 Webster +PJC]

His thefts are too open. --Shak.

That I may find him, and with secret gaze
Or open admiration him behold. --Milton.

6. Not of a quality to prevent communication, as by closing
water ways, blocking roads, etc.; hence, not frosty or
inclement; mild; -- used of the weather or the climate;
as, an open season; an open winter. --Bacon.

7. Not settled or adjusted; not decided or determined; not
closed or withdrawn from consideration; as, an open
account; an open question; to keep an offer or opportunity
open.

8. Free; disengaged; unappropriated; as, to keep a day open
for any purpose; to be open for an engagement.

9. (Phon.)
(a) Uttered with a relatively wide opening of the
articulating organs; -- said of vowels; as, the ["a]n
f["a]r is open as compared with the [=a] in s[=a]y.
(b) Uttered, as a consonant, with the oral passage simply
narrowed without closure, as in uttering s.

10. (Mus.)
(a) Not closed or stopped with the finger; -- said of the
string of an instrument, as of a violin, when it is
allowed to vibrate throughout its whole length.
(b) Produced by an open string; as, an open tone.

{The open air}, the air out of doors.

{Open chain}. (Chem.) See {Closed chain}, under {Chain}.

{Open circuit} (Elec.), a conducting circuit which is
incomplete, or interrupted at some point; -- opposed to an
uninterrupted, or {closed circuit}.

{Open communion}, communion in the Lord's supper not
restricted to persons who have been baptized by immersion.
Cf. {Close communion}, under {Close}, a.

{Open diapason} (Mus.), a certain stop in an organ, in which
the pipes or tubes are formed like the mouthpiece of a
flageolet at the end where the wind enters, and are open
at the other end.

{Open flank} (Fort.), the part of the flank covered by the
orillon.

{Open-front furnace} (Metal.), a blast furnace having a
forehearth.

{Open harmony} (Mus.), harmony the tones of which are widely
dispersed, or separated by wide intervals.

{Open hawse} (Naut.), a hawse in which the cables are
parallel or slightly divergent. Cf. {Foul hawse}, under
{Hawse}.

{Open hearth} (Metal.), the shallow hearth of a reverberatory
furnace.

{Open-hearth furnace}, a reverberatory furnace; esp., a kind
of reverberatory furnace in which the fuel is gas, used in
manufacturing steel.

{Open-hearth process} (Steel Manuf.), a process by which
melted cast iron is converted into steel by the addition
of wrought iron, or iron ore and manganese, and by
exposure to heat in an open-hearth furnace; -- also called
the {Siemens-Martin process}, from the inventors.

{Open-hearth steel}, steel made by an open-hearth process; --
also called {Siemens-Martin steel}.

{Open newel}. (Arch.) See {Hollow newel}, under {Hollow}.

{Open pipe} (Mus.), a pipe open at the top. It has a pitch
about an octave higher than a closed pipe of the same
length.

{Open-timber roof} (Arch.), a roof of which the
constructional parts, together with the under side of the
covering, or its lining, are treated ornamentally, and
left to form the ceiling of an apartment below, as in a
church, a public hall, and the like.

{Open vowel} or {Open consonant}. See {Open}, a., 9.

Note: Open is used in many compounds, most of which are
self-explaining; as, open-breasted, open-minded.

Syn: Unclosed; uncovered; unprotected; exposed; plain;
apparent; obvious; evident; public; unreserved; frank;
sincere; undissembling; artless. See {Candid}, and
{Ingenuous}.


Chain \Chain\ (ch[=a]n), n. [F. cha[^i]ne, fr. L. catena. Cf.
{Catenate}.]
1. A series of links or rings, usually of metal, connected,
or fitted into one another, used for various purposes, as
of support, of restraint, of ornament, of the exertion and
transmission of mechanical power, etc.

[They] put a chain of gold about his neck. --Dan. v.
29.

2. That which confines, fetters, or secures, as a chain; a
bond; as, the chains of habit.

Driven down
To chains of darkness and the undying worm.
--Milton.

3. A series of things linked together; or a series of things
connected and following each other in succession; as, a
chain of mountains; a chain of events or ideas.

4. (Surv.) An instrument which consists of links and is used
in measuring land.

Note: One commonly in use is Gunter's chain, which consists
of one hundred links, each link being seven inches and
ninety-two one hundredths in length; making up the
total length of rods, or sixty-six, feet; hence, a
measure of that length; hence, also, a unit for land
measure equal to four rods square, or one tenth of an
acre.

5. pl. (Naut.) Iron links bolted to the side of a vessel to
bold the dead-eyes connected with the shrouds; also, the
channels.

6. (Weaving) The warp threads of a web. --Knight.

{Chain belt} (Mach.), a belt made of a chain; -- used for
transmitting power.

{Chain boat}, a boat fitted up for recovering lost cables,
anchors, etc.

{Chain bolt}
(a) (Naut.) The bolt at the lower end of the chain plate,
which fastens it to the vessel's side.
(b) A bolt with a chain attached for drawing it out of
position.

{Chain bond}. See {Chain timber}.

{Chain bridge}, a bridge supported by chain cables; a
suspension bridge.

{Chain cable}, a cable made of iron links.

{Chain coral} (Zo["o]l.), a fossil coral of the genus
{Halysites}, common in the middle and upper Silurian
rocks. The tubular corallites are united side by side in
groups, looking in an end view like links of a chain. When
perfect, the calicles show twelve septa.

{Chain coupling}.
(a) A shackle for uniting lengths of chain, or connecting
a chain with an object.
(b) (Railroad) Supplementary coupling together of cars
with a chain.

{Chain gang}, a gang of convicts chained together.

{Chain hook} (Naut.), a hook, used for dragging cables about
the deck.

{Chain mail}, flexible, defensive armor of hammered metal
links wrought into the form of a garment.

{Chain molding} (Arch.), a form of molding in imitation of a
chain, used in the Normal style.

{Chain pier}, a pier suspended by chain.

{Chain pipe} (Naut.), an opening in the deck, lined with
iron, through which the cable is passed into the lockers
or tiers.

{Chain plate} (Shipbuilding), one of the iron plates or
bands, on a vessel's side, to which the standing rigging
is fastened.

{Chain pulley}, a pulley with depressions in the periphery of
its wheel, or projections from it, made to fit the links
of a chain.

{Chain pumps}. See in the Vocabulary.

{Chain rule} (Arith.), a theorem for solving numerical
problems by composition of ratios, or compound proportion,
by which, when several ratios of equality are given, the
consequent of each being the same as the antecedent of the
next, the relation between the first antecedent and the
last consequent is discovered.

{Chain shot} (Mil.), two cannon balls united by a shot chain,
formerly used in naval warfare on account of their
destructive effect on a ship's rigging.

{Chain stitch}. See in the Vocabulary.

{Chain timber}. (Arch.) See {Bond timber}, under {Bond}.

{Chain wales}. (Naut.) Same as {Channels}.

{Chain wheel}. See in the Vocabulary.

{Closed chain}, {Open chain} (Chem.), terms applied to the
chemical structure of compounds whose rational formul[ae]
are written respectively in the form of a closed ring (see
{Benzene nucleus}, under {Benzene}), or in an open
extended form.

{Endless chain}, a chain whose ends have been united by a
link.