哈勃

哈勃的发现哈勃是20世纪美国著名天文学家,他利用天文设备观测,发现离地球很远的天体的光谱都有红移现象,因此他认为这些天体都在远离我们而去,由此他推测整个宇宙在不断地膨胀。哈勃常数根据自己的观测,哈勃得到一个结论:远处天体远离地球的速度和它们到地球之间的距离成正比,这个公式中还有一个哈勃常数,这个常数对于研究宇宙来说十分重要,因为从这个常数可以推导出宇宙的年龄。     

测定哈勃常数的高能路线

测定哈勃常数的高能路线远离地球的强大星系发射的γ射线可能提供一个测量宇宙当前膨胀速度－－哈勃常数－－的方法。该常数对于估计宇宙年龄非常重要，但是其数值的不确定范围达到２倍多。哈勃常数是说一个星系的真正距离与天文学家通常较容易测量出的红移相关。高能γ射...     

哈勃

哈勃的发现哈勃是20世纪美国著名天文学家,他利用天文设备观测,发现离地球很远的天体的光谱都有红移现象,因此他认为这些天体都在远离我们而去,由此他推测整个宇宙在不断地膨胀。     

光谱红移可验证狭义相对论的修正

文中修正狭义相对论重新阐述了引力红移（的空间量）,又由假定引力中心原理阐述了引力红移的时间量,再结合多普勒红移共同解释了类星体的红移机制．其中提出了红蓝移不对称实验室内与星际空间的测量结果不同,并阐明了其原因．还提出了星系臂对称结合修正狭义相对论的实验,用来验证外星系与地球相对远离还是靠近．最后简单介绍了哈勃常数的动态变化．     

哈勃常数和宇宙年龄

在物理宇宙学里,有这样一个著名的定律:来自遥远星系光线的红移与它们的距离成正比。这条定律以它的证实者而命名,即哈勃定律。如果用方程来表示哈勃定律,即v=H_oD。其中,v是由红移现象测得的星系远离速度,也称星际退行速度。H_o是哈勃常数,D     

类星体、能量红移假设及可能的检验

首先介绍了红移及类星体的某些情况及进展。然后提出能量红移的假设g=(E′-E)/E。其次讨论了哈勃常数和红移量子化;按此假设,它可归为能量量子化。最后探讨了可能的检验。     

跟随“哈勃”探宇宙

1990年,哈勃天文望远镜被发射上天。从此,它开始在离地球600千米的高空绕着地球转。让我们一起跟随哈勃天文望远镜来探索宇宙的奥秘吧。     

哈勃探空成就

以哈勃之眼遥望太空,这个视界果然变得前所未有般通透。通过哈勃太空望远镜向地球传送回的宇宙新图景,天文学家对宇宙秘密的认知正在产生革命性的变化。     

20世纪的“伽里略”——哈勃

“哈勃”太空望远镜三年前发射升空,如今修复后正在以它无可比拟的视力,密切注视宇宙变化的一切蛛丝蚂迹。这部“太空神眼”以哈勃为名,可见哈勃在天文领域的重要影响。的确,从事天文研究的人认为,本世纪20年代和30年代,哈勃比伽里略之后的任何一位天文学家都要深刻地改变了人们对宇宙的认识,与当年伽里略坚持把地球从太阳系中心排除相比,哈勃则证明了,银河系不是宇宙     

太空中的星系“帽子”

白日以这小小地球的喧扰,淹没了整个宇宙的沉默.——泰戈尔 星系常被称作“岛宇宙”.人们曾以为银河系便是宇宙的全部,当哈勃空间望远镜把原本被当作是星云的星系认定是另外的“银河系”后,这些分布在各处、由无数恒星构成的天体,便被人们比作了漂浮在茫茫宇宙中像小岛一样的“岛宇宙”.     

卡思卡特城堡

It is worthy of noting that, whilst Crookston Castle witnessed the earlier and happier portion of Mary's variegated life,     

不同的吃喝玩乐

一、吃和喝吃苹果 eat an apple, 吃药 take medicine,吃糖 have some sweets,吃饭 have one's meals,吃馆子 dine out,吃惊 be surprised/     

漏洞百出的教育

Many college freshmen arrive woefully unprepared to do college work, and as disadvantaged populations continue to grow, the share of the American work force that has made it through college is expected to plummet. Many experts blame that educational failure not just on high schools but also on colleges. School & College, a special report by The Chronicle, looks at efforts to fix the system. What reforms would better prepare students for college? What should schools and colleges be doing differently? How should state and federal officials help?     

只要努力,不要后悔

There are numbers of crossroads on our long and unpredictable life journey where we totally have no idea about which direction to choose. No matter what our decision is, we should not turn back, but face the music and go ahead instead. I am this kind of girl who always does try without regretting, one example is how I dealt with my love.     

浅谈移民问题

Migration occurs behind a variety of reasons and has a great effect on the whole world. People may migrate in order to improve their economic situation, or in order to escape civil strife, persecution, and environmental disasters. The impact of migration is complex, bringing both benefits anddisadvantages. This paper briefly talks about the causes of migration, the allocation of benefits, and the ways in which individual countries and the international community deal with this important subject.     

Sister Carrie, an Adherent of Desires

Sister Carrie is one of the most controversial characters in American literature.Thought as a "fallen woman" firstly,she was defined as a "new woman" by some critics later. However, by digging into the motivaton behind the whole process of Carrie's "success", the relationship between Carrie and her creator (the author), the social conditions of then American, it can be found that Carrie has never been free-standing on her thought and she has never found her real-sdf even after becoming a famous actress. In a society dominated by mass consumerism Carrie is only an adherent of her own desires. She also is a representative of all those country girls flooded into cities, a symbol and a sacrifice of the urbanization of America in a time countryside was overcome by cities.     

Improvement of one-cycle controller by use of proportional integral differential controller

1.IntroductionOne-cyclecontrolmethod,whichwasproposedaboutonedecadeago[1],hasbecomeanattractivemethodinspecialfieldssuchaspowerfactorcorrection[2-6],switchingamplifiers[7,8],etc.Themainideaofthiscontrollerisbasedonintegrationofdiodevoltageinone-cycleandforcesittobeexactlyequaltothereferencevalue.Themainadvantageofthiscontrollerisitsrealtimeabilitytorejectthevariationofinputvoltage[1].Despitethisgreatability,ithasnogoodperformancesinrejectingofloaddisturbanceandfollowingreferencecommands.Espec…     

库克斯顿城堡

城堡, 是欧洲典型的建筑之一, 每个城堡都有一个美丽的传说或是一段历史。从本期开始, 我们将推出“城堡之旅”, 带各位读者去浏览、观赏欧洲各地的城堡, 开始一段文化与历史的旅途!     

The Reader Response Approach to Teaching of English Literature

During interview with English majors, it was found that a majority of students expressed disappointment with their experience of English literature classes. Students' dislike of learning English literature appears to be the major problem of teaching English literature in China. Reader response approach is a good way to solve this problem. In this paper, I explain the rationale behind the reader response approach, such as its origin, definition, features, assumptions, and strategies. Then I illustrate how reader response approach works as a teaching strategy by presenting several teaching models. At last I evaluate its usefuiness for teachers and present the advantages of reader response approach in Chinese context.