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We consider an interacting homogeneous Bose gas at zero temperature in two spatial dimensions. The properties of the system can be calculated as an expansion in powers of g, where g is the coupling constant. We calculate the ground state pressure and the ground state energy density to second order in the quantum loop expansion. The renormalization group is used to sum up leading and subleading logarithms from all orders in perturbation theory. In the dilute limit, the renormalization group improved pressure and energy density are expansions in powers of the T 2B and T 2Bln(T 2B), respectively, where T 2B is the two-body T-matrix. Received 19 April 2002 Published online 13 August 2002  相似文献   
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Optical images can be used to transport, store and process information in a parallel way. We discuss different results obtained in the domain of ‘quantum imaging’, aiming at exploiting at the same time the quantum properties of optical images and their intrinsic parallelism. We define the notion of standard quantum limit (SQL) in optical resolution, set by the quantum noise of usual coherent light, and show that it can be much lower than the diffraction limit. We also prove that this limit can be circumvented by especially designed nonclassical and multimode light. We present an experiment showing that OPOs oscillating inside an exactly confocal cavity actually produce such transverse multimode nonclassical light. We finally describe another experiment which has surpassed the SQL in the case of beam positioning, both in the 1D and 2D cases.  相似文献   
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用线性插值法求单摆运动周期的近似解   总被引:6,自引:1,他引:5  
鞠衍清 《大学物理》2006,25(12):32-34
利用线性插值的方法,提出了一个任意摆角条件下的单摆运动周期的近似公式.并利用Mathematica软件将该公式与精确解进行了比较,还与其他近似公式进行了对比.结果表明,该公式的近似程度相当好.  相似文献   
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The solution transformations and properties of the R-matrices for two-component systems under these transformations are analyzed in details.Not all transformed R-matrices can be put into the Skalyanin‘s formalism.For those R-matrices with all required properties,the effects of solution transformations to the six-and eight-vertex systems with open boundary conditions are discussed.these effects can be one of the following types:the Hamiltonian is invariant or transposition-invariant or made in a similarity transformation,or its coupling coefficients are multiplied by an overall factor,or the spin of the system is rotated around the z axis or/and reflected with respect to some plane.In these cases,the transformed systems remain to be integrable.  相似文献   
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Introduction TheTSP50genehasbeenidentifiedasoneofthe testis specificoncogenes,whichisexpressedathigh levelsinapproximately92%ofhumanbreastcancer samples,makingitanattractivemolecularmarkerand apotentialtargetfordiagnosisandtherapy[1].Itisho mologoustomany…  相似文献   
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The structure of luteone (1), a twenty three carbon terpenoid, has been solved by performing a single crystal x-ray analysis on a 3,4-dinitrophenylhydrazone derivative.  相似文献   
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A liquid chromatography/mass spectrometry (LC/MS) method was developed to quantitate and confirm residues of leucomalachite green (LMG) in salmon tissue after their conversion to chromic malachite green (MG) in the extraction process. The method uses no-discharge atmospheric pressure chemical ionization (APCI) in conjunction with an ion-trap instrument to generate product-ion spectra. In the sample preparation procedure, salmon tissue is extracted with acetonitrile/buffer, the LMG residue is partitioned into methylene chloride, the LMG is converted to MG using an organic oxidizing agent, and the MG is isolated on alumina/propylsulfonic acid solid-phase extraction cartridges. The method was validated by fortifying salmon with different levels of LMG, and then detecting the residue as MG The LC/MS conditions, including a comparison of electrospray and no-discharge APCI, were evaluated and optimized. MG was not confirmed in any of the control tissue extracts, and all fortified samples analyzed during validation met the confirmation criteria as described. In addition to providing confirmatory data, this method can provide an alternative method for quantitation of MG in salmon. The recoveries of LMG measured as MG by this LC/MS method, at fortification levels of 1-10 ng/g were very high (86-109%), with low relative standard deviation(RSD) values (6.4-13%). The results agreed very closely with those obtained for the same extracts using an LCNIS procedure, indicating that matrix suppression was not an issue. The presence of LMG in salmon tissue samples fortified at 0.25 ng/g was confirmed by this method, with an average recovery of 70.1% and an RSD of 12.0%. Sample extracts from fish exposed to MG were also analyzed.  相似文献   
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