简谐速度噪声与简谐噪声环境中谐振子的动力学共振

通过求解简谐势场中的广义量子朗之万方程,得到平均能量的精确表达式.由于简谐速度噪声与简谐噪声功率谱的不同特点,两种内部噪声驱动的谐振子在简谐外力的作用下具有不同的共振特征.这些特征可用来检验两种噪声.

水中痕量双酚A的罗丹明6G-动力学共振荧光测定法

目的建立环境水样中双酚A(bisphenol A,BPA)的罗丹明6G-动力学共振荧光测定法。方法向水样品中依次加入0.1 mol/L硫酸溶液0.6 ml,1.0×10-4 mol/L罗丹明6G溶液0.4 ml,0.1 mol/L溴酸钾溶液0.5 ml,70℃水浴加热12 min,流水冷却3 min,在524.2 nm处测定共振荧光强度。结果在0.02~1.40μg/ml线性范围内,该方法所得BPA的回归方程为ΔF=1 708.4c+33.2,r=0.999 8。该方法的检出限为0.014μg/ml,回收率为97.5%~106.5%,RSD为3.9%~5.0%。结论该方法简单、方便、灵敏,适用于饮用水中BPA的测定。

动力学核磁共振波谱学在分子结构研究中应用探讨

探讨用ＮＭＲ研究化学动力学，分析活泼氢的δ值与温度、溶剂、浓度的关系，包括偶合常数对动力学ＮＭＲ研究的影响。并举出实例加以阐述。

基于半导体共振腔的量子位与量子网络构建

以半导体共振腔内光子与原子的纠缠特性作为量子位,通过半导体共振腔电动力学系统将原子态转换成光子态,根据半导体共振腔的工作特性,提出共振腔内原子与光子弱耦合与强耦合的判断条件,并利用外加电磁场对原子的量子态进行操控,从而完成量子逻辑门的操作,再通过各共振腔量子电动力学(CQED)系统间的纠缠进行量子位扩充,实现量子计算与量子网络。介绍微碟型共振腔与单一量子点等多种模型,有助于将量子运算与量子通讯的概念转变为半导体量子器件的研制。

化学反应过渡态的结构和动力学

化学反应过渡态决定了包括反应速率和微观反应动力学在内的化学反应的基本特性,而无论是从理论还是实验上研究和观测化学反应过渡态都是极具挑战性的课题.近年来,我国科学家们利用交叉分子束-里德堡氢原子飞行时间谱仪,结合高精度的量子动力学计算,对H+H2和F+H2这两个教科书式的典型反应体系进行了全量子态分辨的反应动力学研究,从中得出了关于这两个反应体系的过渡态的结构和动力学性质的结论性的研究成果.

金属管杨氏模量与温度关系的实验研究

采用动力学共振法测量不同管径金属管的共振频率,运用origin软件对实验数据进行二次函数拟合,代入管状材料杨氏模量的计算公式得到试样的杨氏模量。通过加热控温设备改变金属管温度,研究金属管杨氏模量与温度的关系。实验结果表明金属管杨氏模量的大小与温度成线性关系。

Full Quantum State Resolved Scattering Dynamics of the F+H_(2)→HF+H Reaction at 5.02 kJ/mol

A crossed molecular beams, state-to-state scattering study was carried out on the F＋H2→HF＋H reaction at the collision energy of 5.02 kJ/mol, using the highly sensitive H atom Rydberg tagging time-of-flight method. All the peaks in the TOF spectra can be clearly assigned to the ro-vibrational structures of the HF product. The forward scattering of the HF product at v′=3 has been observed. The small forward scattering of the HF product at v′=2 has also been detected. Detailed theoretical analysis is required in order to fully understand the dynamical origin of these forward scattering products at this high collision energy.

Microscopic damage and dynamic mechanical properties of rock under freeze-thaw environment

For understanding the rock microscopic damage and dynamic mechanical properties subjected to recurrent freeze-thaw cycles, experiments for five groups of homogeneous sandstone under different freeze-thaw cycles were conducted. After freezethaw, nuclear magnetic resonance(NMR) tests and impact loading tests were carried out, from which microscopic damage characteristics of sandstone and dynamic mechanical parameters were obtained. The results indicate that the porosity increases with the increase of cycle number, the rate of porosity growth descends at the beginning of freeze-thaw, yet accelerates after a certain number of cycles. The proportion of pores with different sizes changes dynamically and the multi-scale distribution of pores tends to develop on pore structure with the continuing impact of freeze-thaw and thawing. Dynamic compressive stress-strain curve of sandstone undergoing freeze-thaw can be divided into four phases, and the phase of compaction is inconspicuous compared with the static curve. Elastic modulus and dynamic peak intensity of sandstone gradually decrease with freeze-thaw cycles, while peak strain increases. The higher the porosity is, the more serious the degradation of dynamic intensity is. The porosity is of a polynomial relationship with the dynamic peak intensity.

Decay Dynamics of N, N-Dimethylthioacetamide in S3（ππ＊） State

The decay dynamics of N, N-dimethylthioacetamide after excitation to the S3（ππ＊） state was studied by using the resonance Raman spectroscopy and complete active space self- consistent field method calculations. The UV-absorption and vibrational spectra were as- signed. The A-band resonance Raman spectra were obtained in acetonitrile, methanol and water with the laser excitation wavelengths in resonance with the first intense absorption band to probe the Franck-Condon region structural dynamics. The CASSCF calculations were carried out to determine the excitation energies and optimized structures of the lower- lying singlet states and conical intersection point. The A-band structural dynamics and the corresponding decay mechanism were obtained by the analysis of the resonance Raman in- tensity pattern and the CASSCF calculated structural parameters. The major decay channel of S3,FC （ππ＊）→S3（ππ＊）/S1 （nπ＊）→S1（nπ＊） is proposed.

Resonance Raman Spectroscopic and Theoretical Study of Geometry Distortion of Thiourea in 2^1A State

The A-band resonance Raman spectra of thiourea were obtained in water and acetonitrile solution. B3LYP/6-311＋＋G（3df,3pd） and RCIS/6-311＋＋G（3df,3pd） calculations were done to elucidate the ultraviolet electronic transitions, the distorted geometry structure and the saddle point of thiourea in 21A excited state, respectively. The resonance Raman spectra were assigned. The absorption spectrum and resonance Raman intensities were modeled using Heller＇s time-dependent wavepacket approach to resonance Raman scattering. The results indicate that largest change in the displacement takes place with the C--S stretch mode u6 （｜△｜=0.95） and noticeable changes appear in the H5N3H6＋H8N4H7 wag v5 （｜△｜=0.19）, NCN symmetric stretch^-C--S stretch＋N3H6＋H8N4 wag v4 （｜△｜=0.18）, while the moderate intensities of 2-15 and 4-15 are mostly due to the large excited state frequency changes of v15, but not due to its significant change in the normal mode displacement. The mechanism of the appearance of even overtones of the S-CN2 out of plane deformation is explored. The results indicate that a Franck-Condon region saddle point is the driving force for the quadric phonon mechanism within the standard A-term of resonance Raman scattering, which leads to the pyramidalization of the carbon center and the geometry distortion of thiourea molecule in 21A excited state.

Structural Dynamics of Phenyl Azide in Light-Absorbing Excited States： Resonance Raman and Quantum Mechanical Calculation Study

The excited state structural dynamics of phenyl absorbing S2（A＇）, S3（A＇）, and S6（A＇） states were troseopy and complete active space self-consistent and the UV absorption bands were assigned on azide （PhN3） after excitation to the light studied using the resonance Raman specfield calculations. The vibrational spectra the basis of the Fourier transform （FT）- Raman, FT-infrared measurements, the density-functional theory computations and the normal mode analysis. The A-, B-, and C-bands resonance Raman spectra in cyclohex- ane, acetonitrile, and methanol solvents were, respectively, obtained at 273.9, 252.7, 245.9, 228.7, 223.1, and 208.8 nm excitation wavelengths to probe the corresponding structural dynamics of PhN3. The results indicated that the structural dynamics in the S2 （A＇）, S3（A＇）, and S6（A＇） states were significantly different. The crossing points of the potential energy surfaces, S2S1（1） and S2S1（2）, were predicted to play a key role in the low-lying excited state decay dynamics, in accordance with Kasha＇s rule, and NT=N8 dissociation. Two decay channels initiated from the Franck-Condon region of the S2（A＇） state were predicted： the radiative S2,min→S0 radiative decay and the S2→S1 internal conversion through the crossing points S2S1 （1）/S2S1（2）.

Kinetics and Mechanism of Catalytic Reduction of U(Ⅵ)with Hydrazine on Platinum Catalysts in Nitric Acid Media

The kinetics of U(IV)produced by hydrazine reduction of U(VI)with platinum as a catalyst in nitric acid media was studied to reveal the reaction mechanism and optimize the reaction process.Electron spin resonance(ESR)was used to determine the influence of nitric acid oxidation.The effects of nitric acid,hydrazine,U(VI)concentration,catalyst dosage and temperature on the reaction rate were also studied.In addition,the simulation of the reaction process was performed using density functional theory.The results show that the influence of oxidation on the main reaction is limited when the concentration of nitric acid is below 0.5 mol/L.The reaction kinetics equation below the concentration of 0.5 mol/L is found as:−dc(UO_(2)^(2+))/dt=kc^(0.5323)(UO_(2)^(2+))c^(0.2074)(N_(2)H_(5)^(+))c^(−0.2009)(H^(+)).When the temperature is 50℃,and the solid/liquid ratio r is 0.0667 g/mL,the reaction kinetics constant is k=0.00199(mol/L)^(0.4712)/min.Between 20℃ and 80℃,the reaction rate gradually increases with the increase of temperature,and changes from chemically controlled to diffusion-controlled.The simulations of density functional theory give further insight into the influence of various factors on the reaction process,with which the reaction mechanisms are determined according to the reaction kinetics and the simulation results.

Assessment of hemodynamics in precancerous lesion of hepatocellular carcinoma:Evaluation with MR perfusion

AIM: To investigate the hemodynamic changes in a precancerous lesion model of hepatocellular carcinoma (HCC). METHODS: Hemodynamic changes in 18 Wistar rats were studied with non-invasive magnetic resonance (MR) perfusion. The changes induced by diethylnitrosamine (DEN) developed into liver nodular lesions due to hepatic cirrhosis during the progression of carcinogenesis. The MR perfusion data [positive enhancement integral (PEI)] were compared between the nodular lesions corresponding well with MR images and pathology and their surrounding hepatic parenchyma. RESULTS: A total of 46 nodules were located by MR imaging and autopsy, including 22 dysplastic nodules (DN), 9 regenerative nodules (RN), 10 early HCCs and 5 overt HCCs. Among the 22 DNs, 6 were low-grade DN (lGDN) and 16 were high-grade DN (HGDN). The average PEI of RN, DN, early and overt HCC was 205.67 ± 31.17, 161.94 ± 20.74, 226.09 ± 34.83, 491.86 ± 44.61 respectively, and their liver parenchyma nearby was 204.84 ± 70.19. Comparison of the blood perfusion index between each RN and its surrounding hepatic parenchyma showed no statistically significant difference (P = 0.06). There were significant differences in DN (P = 0.02). During the late hepatic arterial phase, the perfusion curve in DN declined. DN had an iso-signal intensity at the early hepatic arterial phase and a low signal intensity at the portal venous phase. Of the 10early HCCs, 4 demonstrated less blood perfusion and 6 displayed minimally increased blood flow compared to the surrounding parenchyma. Five HCCs showed significantly increased blood supply compared to the surrounding parenchyma (P = 0.02). CONCLUSION: Non-invasive MR perfusion can detect changes in blood supply of precancerous lesions.

Structural Dynamics of 3-Dimethylamino-2-methyl-propenal in S2（ππ^＊） State

The photophysics of 3-dimethylamino-2-methyl-propenal （DMAMP） after excitation to the S2 （ππ^＊） electronic state was studied using the resonance Raman spectroscopy and complete active space self-consistent field method calculations. The transition barriers of the ground state tautomerization reactions between DMAMP and its three isomers were determined at B3LYP/6-311＋＋G（d,p） level of theory. The vibrational spectra were assigned. The A- band resonance Raman spectra were obtained in acetonitrile with excitation wavelengths in resonance with the first intense absorption band to probe the structural dynamics of DMAMP. The B3LYP-TD computation was carried out to determine the relative A-band resonance Raman intensities of the fundamental modes, and the result indicated that the vibronic-coupling existed in Franck-Condon region. Complete active space self-consistent field （CASSCF） calculations were carried out to determine the excitation energies of the lower-lying singlet and triplet excited states, the conical intersection points and the intersystem crossing points. The A-band short-time structural dynamics and the corresponding decay dynamics of DMAMP were obtained by analysis of the resonance Raman intensity pattern and CASSCF computations. It was found that a sudden de-conjugation between C1=O6 and C2=C3 occurred at the Franck-Condon region of the S2（ππ^＊） state, while the enhancement of the conjugation interaction between C3 and N（CH3）2, and between C1 and C2 evolutions shortly after the wavepacket leaves away the Pranck-Condon region via the excited state charge redistribution. The de-conjugation interaction between C1=O6 and C2=C3 made the rotation of C3=N（CH3）2 group around the C2-C3 bond much easier, while the enhanced conjugation between C1 and C2, and between C3 and N（CH3）2 made the rotation around the C1-C2 bond and C3-N5 more difficult. It was revealed that the initial structural dynamics of DMAMP was predominantly towards the CI-I（S2/S0） point, while the opportunities towards either CI-2（S2/S0） or CI-3（S2/S0） point were negligible. Two decay channels of DMAMP from S2,FC（ππ^＊） to So or Tl,min via various CIs and ISCs were proposed.

BLOOD FLOW PATTERN AND QUANTITATIVE STUDY IN SOLITARY PULMONARY NODULES WITH DYNAMIC CONTRAST-ENHANCED MRI

Objective To evaluate the efficacy of contrast enhanced dynamic MRI in differentiating solitary pulmonary nodules（SPNs）. Methods Eighty-three patients with SPNs undertaken contrast enhanced dynamic MRI. Time-signal intensity curve （T-SI Curve） was made. Peak height （PH） , steepest slope （SS）, maximum enhancement （ Emax ） and the enhancement rates of signal intensity were recorded at the frst （ E1 ）, second （ E2 ）, third （ E3 ） , fourth （ E4 ） , fifth （E5）, and sixth （ E6 ） minute after injection. Results Malignant nodules and inflammatory nodules enhanced significantly higher than benign nodules, and malignant nodules and inflammatory nodules showed obviously higher PH, SS, Emax, El-E6 values than benign nodules （ P 〈 0. 01 ）. There were no sig- nificant differences in PH, SS, Emax, E1-E6 values between malignant nodules and inflammatory nodules （P 〉 0. 05）. Conclusion Contrast enhanced dynamic MR imaging can provide SPNs＇ hemodynamic information and is helpful in differentiating SPNs.

Scheme for Preparation of Macroscopic Multi-component Entanglement in Cavity QED

We propose a scheme of generating multi-component entangled coherent states of cavity fields. In this scheme, the atoms pass through cavities one by one, simultaneously driven by a strong classical field in each cavity. Then the detection of the atomic states collapses the cavity fields onto multi-component entangled coherent states. It is shown that, with a judicious choice of the parameters of the classical field, we can conditionally produce macroscopic multi-dimensional maximal entanglement for the cavity modes.

Determination of Scaling Parameter and Dynamical Resonances in Complex-Rotated Hamiltonian Ⅰ:Theory

In this paper we present a theoretical analysis on the determination of the scaling parameter in the complex-rotated Hamiltonian, which has served as a basis for successful applications of the rigged Hilbert space theory for resonances. Based on the complex energy eigenvalue, E（θ） = ER（θ） - iГ（θ）/2, as a function of the scaling parameter θ, we find that for potential barrier scattering, the condition dГ（θI）/dθ = 0 uniquely determines the scaling parameter 8. The condition d ER （θR）/ dθ = 0 is merely a consequence of the Virial theorem and θI =θR is not a necessary condition for a resonance state. We also provide a harmonic approximation formMism for resonances in scattering over a potential barrier.

Determination of Scaling Parameter and Dynamical Resonances in Complex-Rotated Hamiltonian Ⅱ: Numerical Analysis

This paper is concerned with the determination of a unique scaling parameter in complex scaling analysis and with accurate calculation of dynamics resonances. In the preceding paper we have presented a theoretical analysis and provided a formalism for dynamical resonance calculations. In this paper we present accurate numerical results for two non-trivial dynamical processes, namely, models of diatomic molecular predissociation and of barrier potential scattering for resonances. The results presented in this paper confirm our theoretical analysis, remove a theoretical ambiguity on determination of the complex scaling parameter, and provide an improved understanding for dynamical resonance calculations in rigged Hilbert space.

Adaptive Lagrange finite element methods for high precision vibrations and piezoelectric acoustic wave computations in SMT structures and plates with nano interfaces

This paper discusses the validity of (adaptive) Lagrange generalized plain finite element method (FEM) and plate element method for accurate analysis of acoustic waves in multi-layered piezoelectric structures with tiny interfaces between metal electrodes and surface mounted piezoelectric substrates. We have come to conclusion that the quantitative relationships between the acoustic and electric fields in a piezoelectric structure can be accurately determined through the proposed finite element methods. The higher-order Lagrange FEM proposed for dynamic piezoelectric computation is proved to be very accurate (prescribed relative error 0.02% - 0.04% ) and a great improvement in convergence accuracy over the higher order Mindlin plate element method for piezoelectric structural analysis due to the assumptions and corrections in the plate theories.The converged lagrange finite element methods are compared with the plate element methods and the computedresults are in good agreement with available exact and experimental data. The adaptive Lagrange finite elementmethods and a new FEA computer program developed for macro- and micro-scale analyses are reviewed, and recently extended with great potential to high-precision nano-scale analysis in this paper and the similarities between piezoelectric and seismic wave propagations in layered structures and plates are stressed.

Ten-Dimensional Quantum Dynamics Study of H+CH_(3)D→H_(2)+CH_(2)D Reaction

The mode selectivity of the H+CH_(3)D→H_(2)+CH_(2)D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method.The reaction dynamics are studied for the reactant CH_(3)D initially from the ground state,the CH_(3) symmetry and asymmetry stretching excitation,the CD stretching excitation and the fundamental and the first overtone of the CH_(3) bending mode.The calculated reaction probabilities show that exciting either of the CH_(3) stretching modes enhances the reactivity in the collision energy range below 1.0 eV,while the CD stretching excitation does not obviously prompt the reaction.Fundamental CH_(3) bending excitation has nearly no effect on promoting reactivity.However,a significant enhancement is observed for the first overtone excitation of the CH_(3) bending mode,resulting from the Fermi resonance between the fundamental state of the CH_(3) symmetry stretching mode and the first overtone state of the CH_(3) bending mode.