由于柴油喷入气缸后不会立即着火燃烧,需要经过一小段时间才能着火。

题型:判断题

问题:

由于柴油喷入气缸后不会立即着火燃烧,需要经过一小段时间才能着火。

考点:挖掘机司机考试初级挖掘机司机初级挖掘机司机题库
题型:判断题

如图所示,一质量为m电荷量q的带电微粒,从静止开始经电压为U1的电场加速后,水平进入两平行金属板间的偏转电场中,微粒射出电场时的偏转角为θ。已知偏转电场中金属板长度为L,两板间距为d,重力忽略不计。求:

小题1:带电微粒进入偏转电场时的速率v1

小题2:偏转电场中两金属板间的电压U2

题型:判断题

遗传性乳光牙本质的患者,釉质易从牙本质表面脱落的原因是()

A.釉质牙本质界形态异常

B.牙本质小管排列紊乱

C.牙本质钙化差

D.釉质钙化差

E.髓腔缩小

题型:判断题

擅长治疗阳明头痛的药物是

A.川芎

B.细辛

C.白芷

D.羌活

E.独活

题型:判断题

Most critical plot points in Harry Potter and the Sorcerer’s Stone came from J. K. Rowling’s imagination, but Flamel and his powerful pebble were legendary long before Harry went to Hogwarts. The 14th century alchemist created the philosoper’s stone (called "sorcerer’s" in U.S.editions of Potter ), with which he turned mercury to gold and gained eternal life. But Flamel’s tale—like his stone and his science—was no more real than a magic.

The philosopher’s stone was the key to alchemy, the medieval predecessor to chemistry that aimed to cure all illnesses, make the elixir of life, and transmute base metals into gold. The last made perfect sense at the time. The Aristotelian theory of elements stated that all things consisted of fire, air, water, and earth. So a little shift in one metal’s composition could create gold.

Flamel was renowned as an alchemical success. In 1382, after 25 years of studying an ancient book by "Abraham the Jew", he is said to have produced the philosopher’s stone. His texts, notably a deconstruction of the "Abraham" work, were standard reading for aspiring scientists like Isaac Newton.

Many alchemists believed Flamel faked his 1418 death and that of his wife. Rumored sightings in the 18th century placed them at the Paris Opera. As late as 1816 there were reports of people searching Flamel’s former house for secrets of the stone.

Contemporary historians say, a Nicolas Flamel did live in Paris in the 1300s and endowed many churches and hospitals with his wealth. But he was no alchemist. "He got his money in pedestrian ways—his wife’s earlier marriages, real-estate speculation," says lawrence Principe, author of The Aspiring Adept. Anachronisms, style of language, and the lack of earlier copies indicate that none of "his" writings originated prior to the 1500s.

"This sort of thing happens in alchemy," says Bill Newman, author of alchemical history Gehennical Fire. When an alchemist couldn’t back up his ideas, he might publish them in the guise of a "lost" work. Flamel’s wealth made a good candidate for alchemical identity theft.

Flamel writings and sightings faded with alchemy’s prestige. And the closest anyone’s come to the philosopher’s stone is Rowling. In her hands, it has yielded not just gold but eternal (shelf) life as well.

It can be inferred that Flamel was believed ().

A. to have spend 25 years with "Abraham the Jew"

B. to be the creator of the philosopher’s stone

C. to be the founder of alchemy

D. to have cast light on Newtonian mechanics

题型:判断题

在正常操作下客舱增压是()

A.全自动控制

B.只须输入机场标高

C.着陆后必须人工打开放气活门

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