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373 | 열역학제2법칙을 파괴하는 분자동역학실험 |
포화 R-22의 열역학 특성표
온 도 t℃ |
절대압력 pkg/cm2abs |
비 용 적 |
비 중 |
엔 탈 피 |
증발잠열 rKacl/kg |
엔트로피 |
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액 체 v'l/kg |
증 기 v"m3/kg |
액 체 r'kg/l |
증 기 r"kg/m3 |
액 체 i'Kcal/kg |
증 기 i"Kcal/kg |
액 체 s'Kcal/kg°k |
증 기 s"Kcal/kg°k |
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-70 -60 -50 -45 -40 -35 -30 -25 -20 -15 -10 -5 0 5 10 15 20 25 30 35 40 45 |
0.210 0.382 0.661 0.850 1.078 1.355 1.680 2.060 2.510 3.030 3.630 4.320 5.100 6.000 7.000 8.120 9.350 10.72 12.25 13.94 15.80 17.80 |
0.671 0.683 0.696 0.703 0.710 0.717 0.724 0.732 0.741 0.750 0.760 0.770 0.780 0.790 0.800 0.812 0.825 0.839 0.853 0.867 0.884 0.902 |
0.9380 0.5360 0.3230 0.2560 0.2050 0.1658 0.1353 0.1118 0.0930 0.0777 0.0655 0.0554 0.0473 0.0403 0.0346 0.0297 0.0258 0.0224 0.01944 0.01696 0.01480 0.01296 |
1.490 1.464 1.437 1.422 1.408 1.380 1.381 1.352 1.349 1.333 1.302 1.298 1.282 1.266 1.225 1.219 1.212 1.191 1.172 1.153 1.131 1.108 |
1.0660 1.8657 3.0959 3.9062 4.8780 6.0313 7.2430 8.9267 10.9517 12.8637 15.2671 18.0505 21.1442 24.8139 28.9017 33.6700 38.7558 44.6428 51.4403 58.9970 67.5675 77.1605 |
81.6 84.1 86.7 88.0 89.3 90.6 91.9 93.9 94.6 95.9 97.2 98.6 100.0 101.5 103.0 104.6 106.1 107.7 109.4 111.1 112.8 114.5 |
141.4 142.6 143.8 144.4 145.0 145.6 146.3 146.9 147.4 147.9 148.4 149.0 149.4 149.9 150.4 150.8 151.1 151.4 151.7 152.0 152.2 152.8 |
59.8 58.5 57.1 56.4 55.7 55.0 54.5 53.6 52.8 52.0 51.2 50.4 49.4 48.4 47.4 46.2 45.0 43.7 42.3 40.9 39.4 37.7 |
0.923 0.935 0.947 0.952 0.958 0.963 0.966 0.974 0.979 0.984 0.989 0.995 1.000 1.005 1.011 1.016 1.021 1.027 1.032 1.038 1.043 1.048 |
1.218 1.210 1.203 1.200 1.197 1.195 1.192 1.190 1.188 1.186 1.184 1.182 1.180 1.179 1.178 1.177 1.175 1.174 1.172 1.170 1.168 1.167 |
Second law of thermodynamics "broken" | ||||
번호: 749 | 글쓴이:
냐하하하 |
조회: 19 | 날짜: 2005/02/11 11:52 |
One of the most fundamental rules of physics, the second law of thermodynamics, has for the first time been shown not to hold for microscopic systems.
The demonstration, by chemical physicists in Australia, could place a fundamental limit on miniaturisation, because it suggests that the micro-scale devices envisaged by nanotechnologists will not behave like simple scaled-down versions of their larger counterparts - they could sometimes run backwards.
The second law states that a closed system will remain the same or become more disordered over time, i.e. its entropy will always increase. It is the reason a cup of tea loses heat to its surroundings, rather than being heated by the air around it.
"In a typical room, for example, the air molecules are most likely to be distributed evenly, which is the overall result of their individual random motion", says theoretical physicist Andrew Davies of Glasgow University. "But because of this randomness there is always a probability that suddenly all the air will bunch up in one corner." Thankfully this probability is so small it never happens on human timescales.
Physicists knew that at atomic scales over very short periods of time, statistical mechanics is pushed beyond its limit, and the second law does not apply. Put another way, situations that break the second law become much more probable.
But the new experiment probed the uncertain middle ground between extremely small-scale systems and macroscopic systems and showed that the second law can also be consistently broken at micron scale, over time periods of up to two seconds.
Researchers led by Denis Evans at the Australian National University in Canberra measured changes in the entropy of latex beads, each a few micrometres across and suspended in water.
By using a precise laser beam to trap the beads, the team were able to measure the movement of the beads very frequently, and hence repeatedly calculate the entropy of the system at short time intervals.
They found that the change in entropy was negative over time intervals of a few tenths of a second, revealing nature running in reverse. In this case, the bead was gaining energy from the random motion of the water molecule - the small-scale equivalent of the cup of tea getting hotter. But over time intervals of more than two seconds, on overall positive entropy change was measured and normality restored.
The team say their experiment provides the first evidence that the second law of thermodynamics is violated at appreciable time and length scales.
Their results are also in good agreement with predictions of the "fluctuation theorem", a theory developed at ANU 10 years ago to reconcile the second law with the behaviour of particles at microscopic scales.
"The results imply that the fluctuation theorem has important ramifications for nanotechnology and indeed for how life itself functions", claim the researchers.
Journal reference: Physical Review Letters (vol 89, 050601)
냐하하하 | 흐음 =ㅅ= | [2005/02/11] | |
라임속인생 | 그럼 어떻게 되는걸까;; | [2005/02/11] | |
라임속인생 | 헐 2002년건데 현재는 상황이 어떻게 됐는지 아시는분 있으세요?? | [2005/02/11] | |
냐하하하 | 불확정성원리가 나왔을때부터 미시세계에서의 열역학 법칙의 깨짐은 예상이 되었다고 합니다.. 얼마전에 양자에서 에너지보존법칙이 성립안함을 발견해서 노벨상을 받았다던 글을 봤었는데.. 그래서 찾아봤던 글이죠 ^^a 그거랑 상관없나 ㅡㅡ;; 여담으로 다른 글들도 보고 싶은데 4.95달라를 내라는;(신문사이트;) | [2005/02/11] | |
jys34 | 엔트로피가 수많은 입자계에 대한 상태함수여서 그런 건가요? 미시세계에서는 우리가 사용하던 거시적 양들이 와해되는 경우도 있나 봅니다... 엔트로피를 설명하는 부분에도, 엔트로피가 '증가하는 방향으로 진행될 확률이 엄청나게 크다'고 합니니다 | [2005/02/11] | |
jys34 | 자세히는 모르지만.... Thankfully this probability is so small it never happens on human timescales. 에서도 보듯이 일상적 스케일에서 엔트로피감소 현상은 일어나지 않겠죠.. (글에서도 수많은 분자들이 모두 방구석에 몰릴 확률은 작다..라고 얘기합니다.. 그럼 몇몇 분자만 있으면?확률은 좀 더 커지겠죠?^^;) | [2005/02/11] | |
jys34 | 이 현상을 알아낸 사람들이 연구하는 것도 nano수준의 연구가 아닐까 하네요.. 나노점에서는 온도란 게 정의가 되지 않는다고 합니다. (온도란 것은 수많은 분자가 모여있을 때만 계의 상태를 나타내어주는 물리량입니다. 즉, 운동량이나 운동에너지처럼 분자 자체의 상태를 직접 기술하는 양이 아리나 거죠..) | [2005/02/11] | |
jys34 | QED에서는 전자가 과거로 간 다음(이게 양전자처럼 보이는)에 다시 전자를 흡수하고 미래로 가는 것을 공공연하게 얘기하니... (QED에서 다루는 시간스케일은 여기서 말하는 스케일과 거의 같거나 혹은 더 짧을 수도 있겠죠...) (물론 시간역행에 대한 게 이것과 다르니.... 또 제가 잘못 알고 있을수도-_-ㅋ...) | [2005/02/11] |