نتایج جستجو برای: nuclear spin

تعداد نتایج: 354646  

Nuclear level densities and spin cut-off factors have been deduced for nuclei in the mass region 24‹A‹63,from a microscopic theory, which includes nuclear pairing interaction. Single particle levels for both Seeger and Nilsson potentials were used in the calcdations. Level densities extracted from the theory are compared with their conesponding experimental values, It is found that the overall...

پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشکده علوم پایه 1386

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پایان نامه :وزارت علوم، تحقیقات و فناوری - دانشگاه پیام نور - دانشگاه پیام نور استان خراسان رضوی - دانشکده علوم 1390

برای بررسی خواص هسته ها در مدل های متقارن تاکنون ارایه گردیده که مدل تغییر شکل یافته یا مدل نیلسون یکی از این مدل هاست. علت به وجود آمدن مدل نیلسون ناتوان بودن مدل لایه ای در توضیح ساختار هسته ها در خارج از یک لایه بسته بود. به همین علت شکل هسته ها از حالت کروی به صورت بیضی وار در نظر گرفته شد. مدل نیلسون یکی از موفق ترین مدل هایی است که توانسته است ویژگی های مشاهده شده ذره منفرد در هسته تغیی...

Journal: :journal of sciences islamic republic of iran 0

nuclear level densities and spin cut-off factors have been deduced for nuclei in the mass region 24‹a‹63,from a microscopic theory, which includes nuclear pairing interaction. single particle levels for both seeger and nilsson potentials were used in the calcdations. level densities extracted from the theory are compared with their conesponding experimental values, it is found that the overall ...

2014
Wen-Long Ma Gary Wolfowicz Nan Zhao Shu-Shen Li John J.L. Morton Ren-Bao Liu

Central spin decoherence caused by nuclear spin baths is often a critical issue in various quantum computing schemes, and it has also been used for sensing single-nuclear spins. Recent theoretical studies suggest that central spin decoherence can act as a probe of many-body physics in spin baths; however, identification and detection of many-body correlations of nuclear spins in nanoscale syste...

Journal: :Physical review letters 2011
M S Rudner L M K Vandersypen V Vuletić L S Levitov

We present a scheme for achieving coherent spin squeezing of nuclear spin states in semiconductor quantum dots. The nuclear polarization dependence of the electron spin resonance generates a unitary evolution that drives nuclear spins into a collective entangled state. The polarization dependence of the resonance generates an area-preserving, twisting dynamics that squeezes and stretches the nu...

تکاور, عباس ,

Basic physical principles of nuclear magnetic resonance imaging (N.M.R.I), a nonionizing medical imaging technique, are described. Principles of NMRI with other conventional imaging methods, ie, isotope scanning, ultrasonography and radiography have been compared. T1 and T2 and spin density (S.D.) factors and different image construction techniques based on their different combinations is discu...

Journal: :Physical review letters 2011
Felix Hoehne Lukas Dreher Hans Huebl Martin Stutzmann Martin S Brandt

We demonstrate the electrical detection of pulsed X-band electron nuclear double resonance (ENDOR) in phosphorus-doped silicon at 5 K. A pulse sequence analogous to Davies ENDOR in conventional electron spin resonance is used to measure the nuclear spin transition frequencies of the (31)P nuclear spins, where the (31)P electron spins are detected electrically via spin-dependent transitions thro...

Journal: :Physical review letters 2009
V Jacques P Neumann J Beck M Markham D Twitchen J Meijer F Kaiser G Balasubramanian F Jelezko J Wrachtrup

We report a versatile method to polarize single nuclear spins in diamond, based on optical pumping of a single nitrogen-vacancy (NV) defect and mediated by a level anticrossing in its excited state. A nuclear-spin polarization higher than 98% is achieved at room temperature for the 15N nuclear spin associated with the NV center, corresponding to microK effective nuclear-spin temperature. We the...

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